684 L. A. BORRADAILE. 
arrangement is found in the other subgenera of Lambrus'. In this case, however, there 
are two shallow grooves, an outer one running outward and an inner one running forward 
from the gill-opening, and both uncovered (PI. XLVII. fig. 56). The rough, knobbed back 
of the Parthenopinae is like that of Calappa, but a similar texture is so common among 
crabs that little can be argued from it. Probably it is less conspicuous on a sandy bottom 
with coral pebbles than a quite smooth object would be. 
We have already stated that the Oxyrhyncha are among the sluggish groups of crabs. 
When they are seized they do not attempt to defend themselves with their chelae, but 
move their legs feebly and aimlessly. Indeed the Parthenopinae—like the Calappidae in 
this respect also—often seem to be hypnotised by being moved, drawing up their legs under 
them and remaining still. In general the intelligence of the group is of a low order, with 
the single exception of their cleverness in disguise, which, after all, is probably no more 
than a fairly simple reflex. 

Fic. 122. Elamena gracilis; a. whole animal, b. outside of hand. 
Of the 29 species in the collection made by the expedition, three are new. The rest 
are all recorded from the Indian region by Major Alcock?, with the exception of two which 
were described as new by Miss Rathbun in her account of Prof. Agassiz’s Maldive Crabs’. 
The following systematic list sets forth these species in order. 
Family Hymenosomidae. 
Genus Hlamena H. M.-Edw., 1837. 
1. Hlamena gracilis, n. sp. (Fig. 122) 
Diagnosis: “An Elamena in which the sides of the hinder part of the body are straight 
from the 4th to the Ist pair of legs, and then turn inwards almost at right angles to 
1 Owing to lack of material Iam unable to say whether Journ. As. Soc. Bengal. 
this groove is found throughout Parthenopinae. 3 Bull. Mus. Harvard, xxx1x. 5 (1902). 
2 In his series of papers on the Indian Crabs in the 
