I. '08. 



81 



2,033 fathoms (Smith) ; in Indian waters between 824 and 

 1,310 fathoms (Alcock) ; off the Hawaiian Is. in 293-1,314 

 fathoms (Eathbun), and off the Pacific coast of America in 

 660-1 ,879 fathoms (Faxon). 



Although this species was on one occasion found in a mid- 

 water trawl (S.E. 352), there is evidence to show that the net 

 was actually on the bottom, at any rate for part of the haul. 



Sp. JUV. {nom. incert.) 



Larva allied to Caricyphus, Kemp, 1909, PI. xv, figs. 2-8. 



The specimens found off the Irish coast are, on the whole, 

 considerably larger than those originally described from the 

 Bay of Biscay. The larger examples possess a palp, composed 

 of three rather obscure segments, on the mandible and a stylet 

 at the base of the inner branch of the last four pairs of pleo- 

 pods ; in other respects the appendages differ only very slightly 

 from those of the smaller individuals. The branchial formula 

 appears to be : — 





VIL 



VIII. 



IX. 



X. 



XI. 



XTT. 



XIII. 



XIV. 



Podobranchiae, 



ep. 



ep. 



ep. 



ep. 



ep. 



ep. 



ep. 



... 



Arthrobranchi ae . 







2 



1 



1 



1 



1 



... 



Pleurobranchiae, 





... 





1 



1 



1 



1 



1 



The first four pleurobranchs are large and w^ell developed, 

 but that over the hindmost pereiopod, although about two- 

 thirds the length of that immediately preceding it, is very 

 narrow". All the arthrobranchs are very small, but all, with 

 the exception of the upper one on the third maxillipede, are 

 pinnate. 



When describing this form (1906), I remarked on its re- 

 semblance to some of the members of Spence Bate's larval 

 genus Garicyphus. Some of the ill-assorted larvae in this 

 genus have been relegated to the Hippolytidae, while for 

 others new generic names have been instituted, f have placed 

 the examples here dealt with near the family Nematocar- 

 cinidae, as it does not seem altogether improbable that the 

 form will ultimately be found to represent a stage in the life- 

 history of some species of Nematocarcinus — presumably N. 

 ensifer. 



If this theory should prove correct, it is evident that the 

 rather considerable changes between this form and N . ensifer 

 must take place very rapidly (probably, indeed, accompanied 

 by a shrinkage in total length), for the largest larva found off 

 the Irish coast is 35 mm. in length, w^hile the smallest speci- 

 men of N . ensifer is only 1 mm. longer. 



p 



