1908.] GENUS OP AMPHIPOD CRUSTACEA. 385 



is shorter than the inner, with the outer margin armed with 

 scale-like spines and the inner with strong teeth (fig. 10). The 

 inner ramus has the margins serrated (fig. 9), the under margin 

 beset with two spines in the female and four in the male. 



In the second uropod also, the outer ramus is shorter than the 

 inner. The peduncle is serrated along the distal margin and 

 around the inner angle, with two spines on the angle. The 

 rami as in the first uropod but without spines. The outer ramus 

 of the tfiird uropod is bi-articulate, with a spinule inserted at the 

 outer distal angle of the first joint ; all the margins serrate. 



Telsox (PL XVII. figs. 11 & 12) as broad as long, margin 

 entire. It carries foiu- oblique rows of microscopic spinules, two 

 on each side of the medio-dorsal line, the distal rows longer than 

 the proximal. It is also provided with two rows of tufted setules, 

 four on one side and three on the other (fig. 12), each set in a 

 little pocket (cf. T. raschii, fig. 13). These tufted setules are 

 peculiar to the telson. 



The principal points of difference between this species and the 

 fellowiug, are : — The shape of the rostrum, curved in T. nictcense, 

 horizontal in T. raschii ; the size and niunber of the ommatidia ; 

 the shape of the 2nd, 3rd, and 4th side-plates ; the 2nd maxilla, 

 the inner lobe small in T. nicceense, subequal to the outer in 

 T. raschii ; the maxilliped palp, the first joint long, the second 

 short in T. nic(eense, the reverse in T. raschii ; the shape of the 

 hand of the first gnathopod ; the 1st and 2nd perseopods, the 

 2nd joint being dilated in T. nicceense, the 4th in T. raschii ; the 

 shape of the 2nd joint of the 3rd perfeopods ; and lastly the shape 

 of the telson, the margin entire in T. niccBense, excavated in 

 T. raschii. 



Trischizostoma kasc'hii Esmark & Boeck, 1860. (Plate XVII. 

 fig. 13 ; Pis. XVIIL, XIX. figs. 2-11 ; Pis. XX., XXI. figs. 1- 

 13, 15-18.) 



Sjai. 1860. Trischizostoma raschii Boeck (3). 



1865. ,, „ Lilljeborg (5). 



1870. „ „ Boeck (7). 



1872. „ „ Boeck (8). 



1886. „ ,, Bovallius (11). 



1890. „ „ Sars(13). 



1893. „ „ Delia Valle (15). 



1906. „ nicceense $ Stebbing (19). 



1907. „ raschii stebbing (20). 



The measurements quoted in the follo^ving description are 

 taken from three specimens : an adult female from Norway, 

 measuring 26 mm. from the tip of the rostrum to the tip of 

 the telson ; the immature specimen from the West of Ireland, 

 9 mm. ; and a young one taken from the incubatory pouch of the 

 first specimen, 7 mm. long. The female had seven young still re- 

 maining in the ovisac ; the measurements of their appendages etc. 



25* 



