ALEPAS PARASITA. 163 



conspicuously feathered. The segments of the three 

 posterior pair are not very short or broad ; very slightly 

 protuberant, each with a long transverse, crescentic, 

 narrow brush of bristles, which stand two or three 

 deep in the middle, but on the sides are single : dorsal 

 tufts long, and in the upper segments the spines are thick 

 and claw-like. This structure is common to all the cirri. 

 First cirrus with the rami unequal in length by two 

 segments ; from the shortness of the pedicel, this cirrus is 

 much shorter than the second, but its rami are about two 

 thirds of the length of those of the second cirrus. Second 

 cirrus (and in a less degree the third cirrus), with the 

 anterior ramus a shade broader than the posterior ramus, 

 and rather more thickly covered with spines than are the 

 three posterior cirri. Fifteen segments in the sixth cirrus ; 

 nine in the longer ramus of the first cirrus. 



Caudal Appendages, rather longer than the pedicels of the 

 sixth cirrus, composed of seven cylindrical, tapering seg- 

 ments, each with a circle of very fine bristles on its summit. 



The acoustic (?) sacks are situated some way below the 

 basal articulations of the first cirrus. 



2. ALEPAS PARASITA. 



Alepas parasita. Sander Rang. Man. des Mollusq., p. 364, 



Pl.viii, fig. 5, 1829* 

 Anatifa univalvis. Quoy et Gaimard. Armales des Sciences, 



Nat., torn, x, p. 234, 1827, PL vii, fig. 8. 

 — paeasita. Quoy et Gaimard. Voyage de P Astrolabe, 



PI. xciii, 1834. 

 Triton (Alepas) fasciculatus. Lesson. Voyage de la Coquille. 



Mollusc. PL xvi, fig. 6, torn, ii, part I, 

 1830, p. 442. 



* M. Sander Rang rejects the specific name " univalvis" as signifying a 

 generic character, and he has been followed in this by MM. Quoy and 

 Gaimard themselves. This, according to the Rules of the British Associa- 

 tion, would hardly have been a sufficient reason, but it appears that A. para- 

 sita, like A. minuta, has a pair of horny scuta or valves ; and, therefore, the 



