observed during the Cruise of H. M.S. ' Challenger.' 587 



brought us also an immense ostracod, gigantic if compared to those 

 forms which are known to us as common inhabitants of the fresh and 

 salt water. Its soft sculptured shell has a length of 25 millims. and a 

 height of 16 millims. The small cover formed by two excisions of the 

 shell before the head has by itself the considerable length of 3 millims. 

 I think this is the largest of all Ostracods known, only equalled in size by 

 a Silurian form found in the island of Gothland, and described as 

 Cytherina baltica. According to Quenstedt there seems to have been 

 some doubt whether this is really an Ostracod, as it is ten times larger 

 than any living form hitherto known. This deep-sea form shows that 

 there is no reason for that ; but unfortunately it does not allow me to 

 decide to what family it belongs, for nothing is left of the animal inside 

 the shell but the head with the eyes, the two antennae, and what I con- 

 sider to be a palpus mandibularis. The shell is rather soft and flexible, 

 divided by five lines, originating from a central point in its anterior part, 

 into as many fields, the largest of which on the posterior and inferior 

 side is sculptured. The eyes are very large, pedunculated, and con- 

 sequently movable. So far the description of the animal does not 

 prevent its being put into the family Cypridinidae ; but the antennas 

 seem to me very different from those known in that group ; for here 

 the funiculus antennas primae has got four joints, the last of which has 

 on the upperside an accessory prolongation, which resembles somewhat 

 the scale on the lower antenna of higher Decapoda, but seems not to be 

 in articulation with the funiculus. The flagellum seems to consist of 

 twelve joints with a tuft of hair at the top. But about this number I am 

 not quite sure, as I could not count them in a satisfactory way without 

 spoiling the precious unicum. The lower antenna has, as far as I could 

 make out, only a single flagellum (whereas the Cypridinidae have got two), 

 consisting probably of nine joints. The palpus mandibulae, finally, re- 

 sembles in its shape very much the one which is found among the Decapods, 

 consisting of two joints, the last of which is covered with hairs on its 

 inner side. 



Probably this new and gigantic Ostracod belongs to one of the esta- 

 blished families, a fact which, I hope, will be elucidated by further dis- 

 coveries on our future cruise in the southern hemisphere. 



This is not the only example, however, of gigantic forms in the deep sea, 

 for the same trawlings brought up two specimens (from 1375 and 1600 

 fathoms) of a Gammarid Amphipod the larger of which has a length 

 of 60 millims. and a height of 35 millims. Though we now know 

 that certain Hyperids (Cystisoma Neptunus, both sexes of which we found 

 in the Atlantic, and described in the Phil. Trans. 1873; see also 

 Trans. Linn. Soc. 1875, 2nd ed. Zool. i. p. 24) attain the considerable 

 length of more than 4 inches, these transparent and elongated 

 animals do not make such an impression as the Garnmarids, which are 

 besides in no way peculiar, being perfectly normal, and approaching 



