270 Mr. W. S. Kent on a new S2)ecies o/Sagitta 



midway between these and the large lateral falces (fig. 2, b) ; 

 and it is in reference to the first-mentioned of these structural 

 peculiarities that the specific name of tricuspidata has been 

 applied to it. 



This peculiar armature of the head, just described, is the 

 more easily appreciated when compared with that of Sagitta 

 hipunctata^ represented in fig. 3, and sharply separates it from 

 that or any other recorded species. 



Ym. 1. 



Fig. 2. 



'^'fi 



Fig. 1. Sagitta tncuspidata, nat. size : a, alimentaij^ track ; o, an ovary; 



sp, orifice of one of the spermatic cavities. 

 Fig. 2. Head of the same, viewed from beneath, considerably enlarged : 



a & b, the modified denticles ; c, the lateral falces. 

 Fig. 3. The same region, under like conditions, of Sagitta bipunctata. 



(After Busk.) 



In technical language, the characters of this new form may 

 be briefly drawn up as follows : — 



Sagitta tncuspidata, sp. nov. 



Body long, somewhat stout. Caudal region one-fifth of tlie 

 length of the entire body, exclusive of the head. Lateral fins 

 distinctly separate from one another ; the anterior pair smaller 

 than the posterior. Caudal fin moderately large. Falces bound- 

 ing the lateral margins of the head, eight in number on either 

 side, those occupying a median position being much the largest. 

 The anterior margin of the head bearing a slight prominence 

 on either side of the median line, and in which are inserted 

 three stylate setfe, a similar solitary seta also occupying a 

 central position on each side between these and the lateral 

 falces. 



Entire length of the body 36 millims. ; greatest breadth of 

 the same 5 millims. 



Habitat. The South Pacific. 



The integument of this species, as preserved in spirit, was 

 smooth and very transparent, and appeared to be quite devoid 



