448 On some little-known AmpM^odous Crustacea. 



pleon, and do not extend so far as the penultimate pair. The 

 ivory whiteness of the body is not in any part stained with 

 colour ; but under the microscope pale markings may be ob- 

 served, especially on the dorsal surface, such as are delineated 

 in the accompanying figure (PI. XX. iig. 4). 



In establishing the genus Exungiiia, Mr. Norman considered 

 that his specimen was distinguished from Cratvppus by the 

 remarkable character of the first gnathopods, which have no 

 finger, its place being supplied by a fasciculus of little spines 

 projecting directly forwards. The generic account oWratippus^ 

 on the contrary, had described the first two pairs of hands as 

 subch elate. Nevertheless, both in detail and in general facies, 

 both by figure and description, Cratippus tenuipes and Ex- 

 unguia stilipes so closely resemble one another that it would be 

 a decidedly singular case of mimicry or coincidence of form if 

 they really belonged to distinct genera. But it will be noticed 

 that in the specific description of Cratippus tenuipes the 

 generic account which makes the gnathopoda subchelate is 

 modified by the explanation that the first gnathopoda are 

 scarcely subchelate. Further, these limbs are omitted from 

 the figure of the creature — a fact which is noted but not ex- 

 plained. But any one dealing with a single specimen of 

 Exungida stilipes, which he wishes to describe but not to muti- 

 late, will understand the reluctance with which slender organs 

 such as those under discussion sometimes lend themselves to 

 the manipulation requisite for faithful figuring or accurate 

 description. Packed away as they often are between the coxse, 

 and perhaps more than half hidden by other projecting limbs, 

 one must in such case be content with observing "pas ce qu'on 

 veut, mais ce qu'on peut." Now the fasciculus of little spines 

 which does duty in place of a finger in the first gnathopods of 

 Exungia stilipes can only with great difficulty be distinguished 

 from a finger when the animal is dry ; and even when it is in 

 liquid, the convergence of the hairs or spines often produces 

 a finger-like appearance, especially as the anterior spine or 

 hair is the longest and often takes a slight curve such as is 

 common in the finger of an Amphipod. In the first specimen 

 I myself examined, not only was this appearance decidedly 

 set up, but, by a curious coincidence, two hairs on the palm 

 of one of the second gnathopods produced the appearance of 

 just such a tooth as Mr. Spence Bate figures and describes 

 in that position on one of the second gnathopods of Cratippus 

 tenuipes. 



While, however, the remarkable antennae, the shallow coxse, 

 the relative sizes of gnathopods and pereiopoda, the general 

 appearance of the segments both of pereion and pleon,the telson 



