19 



margin bluntly angled, the inner near the apex produced 

 inward into a tooth. Chelipeds not large in either sex, 

 fingers acute, not leaving an interspace when closed. The 

 four following pairs of trunk-legs not long, subchelate, the 

 sixth joint having a prominence near the middle, and the 

 finger which is strong and acute curving towards it. 



This genus is near to Acanthonyx Latreille (1829) in which 

 the pleon is six-jointed, and to Pugettia Dana 1 1851) in which 

 the trunk-legs are not subchelate. 



Dehaanius dentatus (Milne- Edwards). 



1834. Acanthonyx dentatus, Milne-Edwards, Hist. Nat. 



Crust, vol. I, p. 343. 

 1838. Dehaanius acanthopus, M'Leay, Zool. South Africa, 



Annulosa, p. 58, pi. 3, f. a, b, c. 

 1843. Acanthonyx dentatus, Krauss, Die Siidafi-ik. Crust., 



p. 48. 

 1879. Dehaanius acantJwpus, Miers, J., Linn. Soc. London, 



vol. 14, p. 650. 

 1 886. Dehaanius dentatus, Miers, Challenger Brachyura, 



Reports, vol. 17, part 49, p. 39. 



The sides of the carapace are produced outward each into 

 two triangular teeth ; the anterior is the larger and extends 

 forward ; between them there is sometimes a small blunt 

 process. The surface of the carapace is rather flat, but with 

 various small prominences. The horns of the rostrum are 

 subacute, rather wide apart ; on their bases there are several 

 hooked spines, serrate on the inner margin, but these 

 instruments for retaining extraneous objects are incon- 

 spicuous compared with tne club-like tubules which occupy 

 every prominence. In the pleon of the female there are faint 

 indications in the broad composite segment of the fourth, 

 fifth, and sixth segments, its constituents. 



The eyes, which are darkly pigmented, have a minute 

 projection of the eye-stalk above the oval cornea. 



The longitudinally folded first antennae have numerous 

 plumose setae on the first joint, which is distally narrowed ; 

 the third joint is distally widened, one flagellum lo-jointed, 

 very thick at the base, the other slender, 4-jointed. The 

 second antennae have two joints of the peduncle free, 

 cylindrical, the flagellum slender, pellucid, 7 -jointed. 



The chelipeds have on the fourth joint a line of tubercles 

 and nearly parallel to this a blunt ridge, on the fifth joint 

 two divergent ridges, one of them tuberculate ; the thumb and 

 finger are rather shorter than the trunk of the hand and have 

 each from seven to nine teeth on the opposing edges. The 



