AONIDES OXYCBPHALA. 187 



about 200 segments, tapered much anteriorly and also posteriorly, where it ends in a 

 small tail with eight short cirri, the ventral pair being broadly lanceolate. Dorsum 

 flattened anteriorly, rounded posteriorly; ventral surface grooved. Branchiae con- 

 spicuous, confined to segments two to about twenty-three, of a solid, elongated conical 

 form and both edges richly ciliated. Foot with the dorsal lamella firm and large anteriorly, 

 slipper-shaped or somewhat triangular ; ventral lobe a broad cone. Both diminish after 

 the branchial region to inconspicuous flaps in the middle of the body, again slightly 

 increasing toward the tail. Dorsal bristles capillary, finely tapered, and similar, but 

 smaller forms occur ventrally. Winged hooks appear in the ventral division about the 

 twenty-fifth or thirty-second foot, and in the dorsal before the fiftieth. They have narrow 

 wings, a main fang, and a spike on the crown. 



Colour yellowish or orange, posteriorly brownish. 



Synonyms. 

 1861. Nerine oxycephaly Sars. Christ. Vid.-Selsk. Forhandl., p. 64 (sep. cop., p. 15). 

 1-865. „ „ De Quatrefages. Ann el., t. ii, p. 663. 



1867. Scolecolepis oxycephaly Malmgren. Annul. Polych., p. 91. 



,, Nerine „ idem. Ibid., p. 200. 



1871-2. ? Scolecolepis tenius, Verrill. Rep. U. S. Comm. Fish and Fisheries, p. 601. 

 1879. Scolecolepis oxycephala, Tanber. Annul. Danica, p. 116. 

 1883. Spio oxycephalus, Levinsen. Yidensk. Meddel. Nat. For., p. 100. 



1894. Scolepis oxycephala, De St. Joseph. Ann. Sc. nat., 7 e ser., t. xvii, p. 81, pi. iv, figs. 101 103. 



„ Spio oxycephalus, Bidenkap. Christ. Vid.-Selsk. Forhandl., p. 95. 

 1896. Aonides oxycephala, Mesnil. Bull. sc. Fr. et Belg., t. xxix, p. 242, pi. x, fig. 19—28. 



Allen. Journ. M. B. A., n.s., vol. vii, p. 227. 



Southern. Proc. Roy. Irish Acad., vol. xxviii, p. 235. 



Elwes. Journ. M. B. A., vol. ix, p. 62. 



Augener. Zool. Anzeiger, Bd. xli, p. 264. 



Southern. Proc. Roy. Irish Acad., vol. xxxi, no. 47, p. 100. 



Habitat. — The largest and finest examples occurred in sand between tide-marks, 

 Lochmaddy, Worth Uist; in the same region at Guernsey and Herm; coast of Kerry 

 (A. G-. Moore) ; Torquay (Major Elwes) ; Balscaddon Bay, Howth, Blacksod and Clew 

 Bays (Southern) ; Berehaven (R. I. A.). 



Elsewhere it occurs in Norway in sandy ground (Sars) ; French coast (De St. Joseph 

 and Mesnil); Franz Joseph Land (Augener). 



Head forming a somewhat acute cone, the central ridge from which runs backward 

 to terminate in a small occipital tentacle. The eyes disappear in some preparations, but 

 in others they are very distinct— two on each side arranged in a transverse line just in 

 front of the tentacles, which are of moderate length. 



The body is about 4 inches or more (Mesnil giving 8 centimetres) in length, 

 characteristically tapered in front to the pointed snout, then enlarging for a considerable 

 distance, and again gently tapering to the tail, the slender tip having short cirri. It 

 is somewhat flattened dorsally in front, rounded throughout the rest of its extent, and 

 deeply grooved ventrally. The mouth opens on the ventral surface a short distance 

 behind the tip of the snout. The grouping of the comparatively large branchiae on a 

 limited number of segments (twenty-two to twenty-three) anteriorly, especially as this 



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