posterior and larger portion naked, but muricated with small tubercles arranged in three rows, one down the middle, and one on each side above the bases of the feet: ventral surface smooth, grooved down the middle, more or less iridescent. Head concealed by the front scales, small, tumid, somewhat heart-shaped, sinuated in front, smooth and flesh-coloured; eyes two, very distinct, round and black, placed far back on the occiput and remote from each other. Antennæ three, the mid one originating in the sinus of the head, large and equal in length to the palpi, setaceous, with an abruptly acuminated point, downy, of a dusky colour, but pale and jointed at the base; the lateral antennæ are only about a third the size of the odd one, and of the same form and structure. Palpi two, awl-shaped, larger than the odd antenna, downy or ciliate, and of a straw-yellow colour. On each side of them there is a pair of tentacular cirri equal in length to themselves, but not so stout, and in every respect resembling the mid antenna. Mouth inferior, terminal, furnished with a protrusile proboscis, armed with four jaws of a horn colour, and encircled at the orifice with a series of short conical papillæ. Segments numerous, narrow, deeply incised on the sides, broader than deep. Scales deciduous, rather small, roundish, smooth, with a plain unfringed edge, of a greenish-grey colour, irregularly clouded, and covered with pale puncture-like dots. In all our specimens some pairs had been lost. Audouin and M.-Edwards say there are fifteen pairs, and they are affixed to every alternate segment after the fashion of the more normal species of the genus. The anterior pairs are imbricated and cover the back entirely, but the posterior pairs lie over the bases of the feet, and leave the back naked in the middle. Feet well developed, homologous; the dorsal branch represented by a mere tubercle, from which grows a fan-shaped brush of short stout equal bristles; the ventral branch conoid, protruded much beyond the dorsal, obliquely truncate, armed with a series of golden-yellow strong bristles, and with a small inferior cirrus which does not extend beyond the apex. Bristles of the dorsal branch somewhat curved, rather obtuse, rough on one side, and generally soiled with extraneous matter; those of the ventral branch more than twice as long, decreasing both in strength and length as the series descends to the belly, the two upper ones pointed like a lance, the rest like a hedge-knife, with two sharp denticles at the tip, and the inner edge of the curved part minutely serrulated. Spines yellow, tapered insensibly to a rather obtuse point, one to each brush of bristles. Tentacular cirri awl-shaped, abruptly acuminate, downy or ciliate, of a dusky or dark colour, with paler spots, reaching to or a little beyond the apex of the foot; all the feet posterior to the 31st pair are furnished with these cirri, but only those anterior to them which are destitute of scales. Tail without elongated styles. It is difficult to describe the colouring of this fine worm. Of specimens preserved in spirits the ground colour is a straw or ochreyellow, but the back is clouded and spotted with dusky olive-green, there being a row of spots down the middle, a line or band along each side, and another row of spots exterior to this above the bases of the feet; and these markings correspond with the arrangement of the tubercles which roughen this surface. The number of segments is liable to vary. Audouin and Edwards say that there are 82 of them. In one specimen we found them to be about 80; but that which served for our figure, and which was twice the length of the other, had not less than 110. (a) Falmouth. PLATE IV. Fig. 1. Polynoë scolopendrina of the natural size. 2. The head with its appendages, highly magnified; the front scales have been removed. 3. The proboscis laid open. 4. Section of a segment, showing the squamous feet; the scales have been raised and reverted. 5. A scale. 6. One of the cirrigerous feet. 7. A bristle of the dorsal brush. 8. The upper bristle of the ventral brush. 9. One of its under bristles. 4. PHOLOË*. Pholoë, Johnston in Ann. Nat. Hist. ii. 428. Oersted in Kroyer, Char. Body linear-oblong, the scales placed over every alternate foot; cirri none or rudimentary; proboscis with four corneous jaws, the orifice plain; antennæ five, unequal, distinct; palpi two, large: eyes two or 4: branches of the foot connate, the bristles of the superior capillary, of the inferior falcate. 1. Ph. inornata, scales covering the back partially, fourteen pairs, roundish or oval, smooth, spinous on the outer edge; eyes two. Length 6""; breadth 1"". Plate V. figs. 1-5. Palmyra ocellata, Johnston in Zool. Journ. iii. 329. Pholoë inornata, Johnston in Ann. Nat. Hist. ii. 437. pl. 23. f. 1-5. Hab. The littoral region. Amongst Confervæ between tide-marks. Berwick Bay, rare. Desc. Worm half an inch in length, scarcely a line in breadth, almost linear, but a little narrowed behind, rounded at the extremities, flattened, of a yellowish-brown colour, dusky along the sides, and marked there with a series of paler round spots indicating the point of fixture of the scales. Head small and obscurely defined, corneous. Eyes two, very distinct, black, placed backwards. Palpi long, conical, smooth, jointed at the base, pointing forwards. Antennæ five, the outer pair larger than the three intermediate, and fringed on the inner sides with a few fleshy spines; the odd antenna * A Nereid: "As Pholoë, most that rules the monsters of the main." superior and small. Mouth inferior, provided with a firm cartilaginous proboscis armed with two pairs of jaws similar to those of the Sigalion, but the orifice appears to be plain. Body with about forty pairs of feet, which seem to be all alike and destitute of tentacular cirri, but we find two minute fleshy papillæ near their bases on both the dorsal and ventral sides. The feet are not distinctly divided into two branches, but there is a fleshy fold behind the apex, and within which the apex can be retracted. From this fold there originate two bundles of simple bristles, one dorsal and the other ventral, the bristles short; the apex itself is armed with a bundle of compound bristles, jointed near the point, and fashioned like those of a Polynoë; to each brush of bristles there is a conical spine placed in the centre of the brush. The back of the worm is partially covered with a row of scales placed over the bases of the feet down each side, but the middle of the back is naked. There are fourteen pairs of scales, some of them round, others oval, all spinous on the outer edge, smooth, raised in the centre. Belly smooth, fleshcoloured. Posterior extremity without styles. PLATE V. Fig. 1. Pholoë inornata of the natural size. 2. The anterior portion of the body, magnified. 3. The proboscis laid open, magnified. 4. Two of the dorsal scales. 5. The foot. 2. Ph. eximia, scales twenty-six pairs, imbricate, covering the back, reniform, spinous on the posterior edge; eyes two; anal styles prolonged. Length 6"". Pholoë eximia, F. D. Dyster in litt. Hab. Tenby, Frederic D. Dyster, Esq. Desc. "Body about half an inch long, attenuated slightly towards the tail, which is obtuse. Scales twenty-six pairs, the second and twelfth inclusive marked with a dark irregular spot about the centre, reniform, armed with from six to ten stout hairs, which, from the twelfth pair of scales to the tail, extend towards the middle of the back, and give the worm a spinous appearance. Scales covering the back. Segments thirty-seven; the first pair of scales attached to the first segment, the eleven next to alternate segments, the fourteen last to every segment. Antennæ five, of about equal length, the median and external rather stouter than the internal pair. Ocular spots two. Tentacular cirri very thick at the base, and about four times the length of the antennæ, ringed. Tail terminated with two long subulate styles. Proboscis cylindrical, three times as long as broad; no appendages at the orifice. Jaws four, incurved, not denticulated. Dorsal bristles very slender, short, finely denticulated, disposed in a fan-like bunch. Ventral bristles much longer and thicker, the terminal joint slightly incurved, very finely denticulated both on the terminal joint and on the anterior portion of the summit of the shaft. Ventral setiferous tubercle large and well developed; the dorsal very small and inconspicuous."-F. D. Dyster. 5. SIGALION*. Sigalion, Aud. & M.-Edw. Litt. de la France, ii. 103. Cuv. Règn. Char. Body linear-elongate, the scales and superior cirri coexistent on the same feet, the former placed over every alternate foot until the 27th segment, whence they follow uninterruptedly to the anal extremity proboscis with corneous jaws; antennæ three; palpi two, large; eyes four, concealed: feet biramous: anal segment with two styles. This genus is distinguished from every known Annelid by the coexistence of superior cirri and scales on the same foot. The body is elongate, depressed, almost linear, and formed of numerous segments. The disposition of the cephalic extremity is singular; for the head, in place of being exactly terminal, is overtopped by the first pair of feet, which are lodged underneath it, and more or less approximated to the mesial line. In our native species there are three cranial tentacula, but in a foreign species the odd one is wanting, and the lateral are always small, and lie upon the peduncles of the first feet. The palpi, on the contrary, are long, and are placed outside and under these feet, of which the two terminal cirri are pointed forwards, and may be mistaken for true antennæ. There appear to be no eyes. The mouth is inferior, and is the outlet to a proboscis similar to that of Polynoë, but armed with less powerful jaws. At the superior base of every foot there is a rounded protuberance which gives origin to a cirrus, and which also carries a scale on such feet as have this appendage,—a fact inconsistent with the theory which maintains that the scales are mere modifications of the cirri. On the anterior part of the body the scales appear and disappear on every other segment, but subsequent to the twenty-sixth pair of feet there is one to each segment, and two or more to the last two segments, so that their number is always considerable. The feet are distinctly divided into two branches; the superior branch terminated with a single brush of bristles, the inferior sometimes with one and sometimes with two, but the bristles are shorter. The inferior cirrus is very obvious, and is inserted far from the extremity of the foot. The appendages of the anal ring form two tentacular styles. As to the branchia, there is no trace of them at the base of the feet, and when Audouin and Edwards inform us that they seem to be replaced by the fringes which garnish the external margin of the elytra, they surely forget that these fringes are not more developed than they are in Polynoë, and their structure is very unlike that of a respiratory organ. * Perhaps formed from oiyaλóeis-curiously or anomalously made-but Sigalion is a name of Harpocrates, the companion of Esculapius and Hygeia, by whom physicians were obliged to swear that they would observe a religious silence in their profession. See Sprengel, Hist. de la Médecine, i. 136. 1. S. boa, scales entirely covering the back, reniform, roughish, ciliated on the external margin; lateral antennæ a common stalk, with three setaceous palpiform appendages articulated on its top. Length 8"; breadth 4"". No. XIX. and Pl. V. fig. 6–15. Sigalion boa, Johnston in Loud. Mag. Nat. Hist. vi. 322 (1833), Sigalion Idunæ, H. Rathke in Nov. Act. Acad. Cæsar. Nat. Cur. xx. Hab. The littoral region near low-water mark. Desc. Body seven or eight inches long, linear, flattened, slightly tapered towards the tail, the anterior extremity obtuse and somewhat rounded, the beak covered with two rows of scales of an ash or some No. XIX. с b. A scale enlarged. a. Sigalion boa of the natural size. times reddish-brown colour, but as some of the scales are often paler or whitish, the body then appears piebald. Head small, convex, corneous, concealed by the rounded anterior pair of scales, terminated in front with three short setaceous two-jointed antennæ, the central one larger and longer than the others. Eyes none, but at the base of the least antennæ there are two depressed punctures very like eyes. Palpi two, setaceous, half an inch long, arising above and at the sides of the mouth. Mouth inferior, furnished with a retractile |