SCHIZOI'ODA. 3 



said to have mched that state. Still, they afford material for a rc-lc.s. ripti<>n and 

 figures of the s{x-< i<-> in the adult state, with some notes on the growth change*. 



Tin- M\-i'lacea consist of eleven specimens, referable to six species. The most 

 interesting of these species is Ifanscnomysis anttirctioi, an Antarctic representative of 

 genus hitherto known from hut three specimens from Arc-tit- and Itoreal waters. 



The chief interest of the collection lies in the evidence which it may afford as to 

 the similarity or dissimilarity of the fauna at the two poles. There are no species 

 common to the fauna of both polar regions in the collection ; hut, on the other hand, 

 all the genera save one, Antarclomysi*, are represented in northern waters hv species 

 which arc quite distinct from their southern allies. 



Exploration of the bottom fauna of the deep waters of the globe, especially in 

 tropical and sub-tropical regions, is as yet only in its infancy, and it is therefore 

 extremely probable that what are now known to In- bipolar genera and species will in 

 future be found to IK? cosmopolitan in their distribution. The Schixo|oda were lonj.' 

 thought to have in Lopkogatttr typicw* a stock instance of a bipolar form, but the 

 gaps in ita distribution have \tccn almost completely filled up as a result of recent dcep- 

 sca work, and, with the exception of the tropical Atlantic, it* range is known to be 

 complete from Norway to the Cape. 



Two bipolar species of Mysidse are known, however Boreomyisi* Hcyplmjix, G. O. 

 Sarn, from Arctic waters, and Lat. 50 8., near the Crozct Islands, and J /;<////</<* 

 crozetti, from the seas of Greenland and Ian Mayen in the north and the Crozet Islands 

 in the south. They are not known from the intermediate waters. 



Of the genera of Antarctic Schi/opoda, Eupluiw'ui, T/iymtiwessti, and Euctip'm are 

 world-wide in range, but the northern and .southern species are quite distinct, even the 

 hitherto supposedly cosmopolitan Ewwpiti aufitralis, Hansen having shown to contain 

 at least two species, probably three. 



P*fiuloinmn t Hansenomysis, DactylanMyttps, and Mytidetf* are, as at present 

 known, bipolar genera, but Psetulomma, at least, ranges far from both poles, and 

 further exploration will prol>ably extend the known range of the other genera also. 



The most interesting case is presented by the genus Anturclninyxitt. It is rlo.--ly 

 related in structure to the northern species Michtheimy*i* mijcta (Lilljeliorg), a species 

 inhabiting chiefly the colder waters of the northern hemisphere. The two genera arc 

 separated only in the characters of the male pleopods, which are more primitive in the 

 Antarctic form, and neither genus is likely to he found to have a distribution which 

 extends very far from the poles they frequent 



In the preparation of this report I have received much valuable help from many 

 sources. The authorities of the British Museum kindly allowed me to examine and 

 dissect two specimens from the 'Challenger' collections in their charge. To Dr. 

 Caiman, of the British Museum, I have been much indebted for information on many 

 points connected with the 'Challenger' material, and he has. also, at my request, 

 furnished me with drawings of various species. Mr. E. \V. L Holt kindly examined 



