1 98 On a 7iew species of the Genus Alcpas. 



are longer than those of the anterior ramus and the terminal 

 joints are thinner, while keeping about the same length. 



2nd pair. — The rami are nearly equal to each other and 

 about twice as long as the posterior ramus of the first pair; 

 that is to say they attain 12 millim. with 50 to 55 joints, the 

 joints at the base not being very distinct. These segments 

 are short, straight, and each bears some long anterior bristles 

 and some shorter and finer posterior bristles only at the border 

 of the segments. 



The 3raf and 4th pairs are almost exactly similar to the 2nd. 



The bih pair has the inner ramus atrophied. The length 

 of ibis ramus does not exceed 3'5 to 4 millim. ; the number of 

 joints is 19, long and slender towards the extremity, bearing 

 some long fine bristles on the anterior margin and two or 

 three very short bristles on the posterior margin, at the 

 border of the segments. The normal ramus is similar to the 

 preceding. 



Finally, the Qth pair of cirri have also the inner ramus 

 atrophied, similar to the preceding, however^ but shorter (16 

 joints) (fig. 10). 



Caudal appendages. — These are long, slender, and cylin- 

 drical (I'D millim. in length, with 10 joints). The basal 

 joints are very broad compared with the superior (fig. 9). 

 'i'lie last joint is furnished with fine bristles longer than itself; 

 but these diminish rapidly in length as they approach the 

 base until they become simple spines. 



Filamentary appendages. — A single very short pair at the 

 base of the first pair of cirri. 



Penis. — The penis, which is about \'6 millim. in length, 

 is neaily regularly cylindrical, terminating at its extremity 

 in a blunt point (fig. 11). It is covered with a thin transparent 

 cuticle having annular parallel folds in the depressions, be- 

 tween which are placed, quite irregularly, long fine bristles 

 more or less bent, which form at the apex a somewhat irregular 

 tuft. 



This new species, to wliich I propose to attach the name 

 of the Director of the British Museum, approaches in some 

 of its characters A. cornuta, Darw., and A. japonica, Auri- 

 villius, but it has most affinity with the first-mentioned 

 species. 



Bordeaux, 

 7 .May, I'JOO. 



EXPLANATION OF PLATE VIIL 



Tig. 1- Alepas Lankesteri, sp. n. 



Fitj. 2. Hook-ehaped processes on the cuticle of the capitulum. 



Fig. 3. Conical processes on ditto. 



