observed during the Cruise of H. M.S. ' Challenger. 3 589 



The same petaliform organs, but on much shorter stalks and of 

 different size, are met with in another animal which came up in these 

 dredgings, and which belongs to the proper Mysids, as its carapax is not 

 loose, as in Petalophthalmus, but adheres to the segments of the pereion, 

 as in ordinary' shallow- water Mysids. It has a length of 35 millims., 

 and, being a male, is distinguished by two, small, tube-like copulative 

 organs at the base of the last pair of pereiopods. A form of the same genus 

 was afterwards found in shallower water near Kerguelen, the females of 

 which had got young ones in their pouches, showing that they undergo 

 the same metamorphosis as Mysis does. They are in consequence 

 closely allied to this genus, and have nothing to do with Petalophthahnus, 

 though the eyes have undergone the same retrogressive metamorphosis as 

 in this genus. 



In these dredgings we caught several of the higher Decapods, G-alatheas, 

 several specimens of Pagurus, and Caridid as well as Peneid shrimps. 

 One of the Caridids was important to us, as it was the same species 

 which we had formerly got in quantities in deep water off the coast 

 of Brazil between Pernambuco and Bahia. It has a very solid and 

 spiny carapax and large eyes. From a morphological point of view all 

 these crabs and shrimps have, however, scarcely any interest. 



When cruising near the Crozets we dredged in a depth of 210 fathoms, 

 where only a Serolis was got, and again in 550 fathoms, where no 

 Crustacea came up at all. 



In Kerguelen Island, where we stayed nearly a month, much shallow- 

 water dredging took place in the different harbours, most of which was 

 done by Prof. Wyville Thomson himself, while I was on shore collecting 

 the land animals of the place. There is no Gammarus with terrestrial 

 habits nor any Oniscas to be found in these barren islands, animals 

 which still exist on the Tristan d'Acunha Islands. In the pools on shore, 

 however, a small brachyurous crab was found, which was never got by the 

 dredge not even in the shallowest water. Also in the pools it is by no 

 means common, so that I only got three specimens. One of these, a 

 female, had empty eggshells attached to its pleopoda ; and I think that a 

 small Zoea, the only larva of higher Crustacea which I was able to get on 

 the surface, belongs to this species; for all the dredgings down to a 

 hundred fathoms near Kerguelen Land never yielded any of the Decapod 

 Crustacea except the small Mysid which has been already mentioned. 



The shallow-water fauna near Kerguelen may be divided into two 

 zones — the one going from a few fathoms down to forty, and charac- 

 terized by small silicisponges, a Spatangus, Cribrella, and especially by 

 Serolis ; and the second from 40-120 fathoms, inhabited by large silici- 

 sponges (Bossella antarctica, Carter), a large red Euryal, Comatula, another 

 Serolis, by Cuma, Tanais, and Anceus. These two zones of course are not 

 strictly separate, as many of their inhabitants go from one into the other ; 

 but I do not think, for example, that Spatangus will be found to be any- 



