made during the Voyage of H.M.B. e Challenger. 3 §77 



In a very successful dredging in 450 fathoms off St. Thomas we got 

 an Astacid, which I have described and figured under the name of A. 

 zaleucus, as it is totally without eyes or even a trace of eye-stalks, and 

 is distinguished by an enormous development of the right claw. The 

 animal has never been got since, but may perhaps, when a female shall 

 have been found, form the type of a new genus. In the mean time I 

 have called it Astacus, as it seemed to be nearer to the crayfish than to 

 Nephrons, to which it would be convenient in so far to put it, as this, 

 genus contains only salt-water forms. This is a question which has to 

 be decided by those who, after us, will be fortunate enough to dredge up 

 some more specimens of it. 



Another Decapod, of which two species were got in the Atlantic, is 

 Willemoesia, a genus established by Grote, and first described by us under 

 the name of Deiclamia. I have shown in my paper that these crayfishes 

 are so nearly allied to the fossil Eryonidae (from the Solenhofener 

 Schiefer), that it becomes doubtful whether a new genus is to be esta- 

 blished for them at all. If, as lately has been maintained by Mr. "Wood- 

 Mason, these Crustacea have already been described by Heller under the 

 name of Polycheles, from a specimen which was got in the Mediterranean 

 near the coasts of Sicily, this will of course be the name to be adopted. 

 I am unable for the present to compare Heller's figure with our speci- 

 mens, and shall have to reconsider the question when working out the 

 Crustacea of this expedition. There are some points in Heller's descrip- 

 tion which still make me doubtful about it ; and in order not to confuse 

 the matter more, we shall call these Crustacea Willemoesia until we re- 

 turn to Europe. Anyhow, it is very interesting that cousins of the famous 

 Jurassic Eryonidai are still living in the great depths, ivhere they are (in 

 the Pacific at least) by no means rare. 



The two species found in the Atlantic are both blind : one of them, 

 Willemoesia leptodactyla, has been only found in very great depths ; the 

 other one, W. crucifer, was brought up off St. Thomas (~W. I.) from a 

 depth of 450 fathoms. We shall below have to mention a third species, 

 which we have very often got in the tropical parts of the Pacific. 



Of Palinurids we got here only one form, a small species with eyes 

 partly hidden under the rostrum, which I shall only describe after our 

 return, as it might possibly be known already. 



The anomurous Crustacea Pagurus and Oalathea are very common in 

 deep water, especially the former, which very often carries about a large 

 Palythoa, which itself has nearly absorbed the calcareous substance of the 

 shell on and in which both animals originally settled. The Oalathea has 

 been got with and without eggs ; and it appears that one whitish species, 

 which inhabits the great depths, is to be found in all the seas. 



Brachyura were very rarely brought up ; we had once, from 600 

 fathoms, a very large red crab, and from 1675 fathoms a blind spiny 

 larva of a crab, which was in the Megalopa-stage, and is all the more 



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