668 ON CRUSTACEA BROUGHT BY DR WILLEY FROM THE SOUTH SEAS. 



This genus, though very near to Caligus, seems to be sufficiently distinguished from 

 it by the entire disappearance of the furcula, the peculiar character of the abdomen, 

 and perhaps it may be added, by the habitat of the tj'pe species. 



Name from a-yx'', near, and Caligus. 



Anchicaligus NAUTILI (Willey). 

 Plate LXXI. 

 1896. Caligus nautili, Willey, Quart. Journ. Micro. Sci., vol. 39, p. 145. 



In general shape and proportions this species bears a close resemblance to Oaligus 

 abbreviatus, Kroyer, and consequently also to Caligus centrodonti, Baird, though it is 

 separated from both by generic characters. The carapace is only a little longer than 

 broad, but greatly longer than the rest of the body, in the male even more than 

 double as long. The genital segment is broader than long, little more than half the 

 width of the carapace in the female, less than half in the male. The small abdominal 

 segment is more than half as wide as the genital segment in the male, and less than 

 half in the female. 



The frontal plate has a slight central notch over a small oval clear space 

 (described in Kroyer's species as ' orange-shaped point of attachment ') and its corners 

 are occupied by large almost circular lunules, abutting upon which are the first 

 antennae, two-jointed, the second joint much narrower than the somewhat ovoid first. 

 The second antennae have a hooked terminal joint, the basal seemingly longer in the 

 male than in the female. 



Between the second antennae, a little below them, and just over the base of the 

 rostrum, are the two eyes, 'spectacle-eyes' according to Dana's expression (U. S. Expl. 

 Exp., Crust., p. 1315). Of these he says (p. 132-5), ' Besides the ordinary simple eyes 

 in the Caligidae, there is sometimes a pair of simple eyes with large prolate lenses 

 and oblate conspicilla or broad convex corneas as in our genus Specilligus.' In 

 describing that genus, he says (p. 1374), 'The essential point of difference between 

 this genus and Nogagus, is the existence of two large transpai-ent lenticular corneae 

 (conspicilla), exactly like those of the Sapphirinae. These conspicilla are attached to 

 'the exterior shell, but with some difficulty may be separated. On pressure they proved 

 to be brittle, though rather hard. The lenses of the eyes are situated below, near 

 the conspicilla, though a little nearer the median line. Between the two there is a 

 minute coloured spot.' The species, Specilligus curticaudis, was taken from the body 

 of a shark, off New Zealand. ' The pigment of the two eyes was deep blue ; the 

 colour of the minute spot between, bright red.' Steenstrup and Ltitken (op. cit, 

 p. 50) threw out the suggestion that Dana's Nogagus validus and his Pandarus brevi- 

 caudis, taken at the same time with his Specilligus, may be the same species. It may 

 be remarked that all three are clearly distinguished from Anchicaligus by the absence 

 of lunulae. In the species now under description the prominent eyes differ from those 

 described by Dana by having the conspicilla adjacent above, and the lenses a little 

 remote. No median spot could be perceived, but that and the eye pigment may easily 

 have disappeared in spirit. 



