272 DR. W. A. CUNNINGTON ON 



Dimensions as follows : — 



Adult male (largest specimen). Adult female (lai^gest specimen). 



mm. mm. 



Totallength 6-6 Total length 11-4 



Length of carapace ... 3*8 Length of carapace ... T'O 



Breadth of carapace... 3'4 Breadth of carapace... 6*0 



Remarks. — While exhibiting no very outstanding character- 

 istics, this species is sufficiently well defined by a number of 

 minor differences affecting several parts of its external anatomy. 

 There are only a few specimens in the collection, and, as is usual, 

 the small ones differ to a certain degree from the large. In the 

 smaller specimens the antero-lateral depressions are less pro- 

 nounced, and the anterior hook on the antennules is less marked 

 or even absent. 



In default of a name more obviously suggested by its anatomy, 

 the mask-like appearance of the carapace is alluded to in its 

 specific name. 



Occurrence. — Ndanvie, 7/2/05. From mouth-cavity of several 

 specimens of Bathyhates ferox. Three males, two females. 



Argulus exiguus, sp. n. (PI. XLII. fig. 9 ; PI. XLIII. 

 figs. 21, 22.) 



Description. — Carapace (in the male) elliptical, considei'ably 

 longer than broad, with slight antero - lateiul depressions. 

 Posterior lobes moderately broad, rounded, covering bases of all 

 swimming-legs, and separated by moderately broad sinus one- 

 third the length of the carapace. The edge of the carapace 

 below is armed with small spines which extend to the region of 

 the swimming-legs. Abdomen in the male slightly longer than 

 broad, about one-quarter entire length of body ; posterior lobes 

 bluntly pointed and separated by moderately broad sinus almost 

 one-quarter length of abdomen. The furcal appendages lie at the 

 bottom of the anal sinus. Antennules and antennae rather small, 

 but moderately armed, appi'oaching somewhat to one another in 

 the mid line. Basal segment of the antennule with posterior 

 spine ; second segment with blunt anterior spine, posterior 

 spiniform process, and slender lateral hook. Antennae with slight 

 spiniform projection on basal segment. Immediately behind the 

 insertion of the antennule is situated a stout accessory spine. 

 Eyes very large, a little more than one-quarter breadth of 

 carapace apart and somewhat far forward. Suckers of moderate 

 size, -IS-'IS of breadth of carapace. Maxillipeds strong and 

 well armed ; basal segment produced into three stout spines ; 

 "area" of fair size, roughly oval, and armed with small spines. 

 A pair of stout accessoiy spines is situated between the bases of 

 the maxillipeds, and a second pair, rather slighter, a short 

 distance behind them. Flagella pi'esent on the first two pairs of 

 swimming-legs. In the male, vesicula seminalis present on the 

 third leg, copulatory peg and accessory cushion on the fourth. 



