924 ON ISOPODA COLLECTED BY THE ' CHALLENGER.' [DeC. 1, 



Keigueleii in the southern hemisjihere, and Station 252 in the 

 middle of the North Pacific) yielded examples of the family. The 

 distribution of this family over the floor of the ocean appears to be 

 much wider than that of any other family of the Isopoda. While 

 the genera Serolis, Arcturus, and others, of which the ' Challenger ' 

 obtained specimens from the deep sea, were almost invariably 

 obtained in the immediate vicinity of land, this was by no means 

 invariably the case with the Munnopsidse. 



Tlie frequent occurrence of more than a single species at the same 

 station appears to show that this family is largely represented in 

 the abyssal fauna. At Station 146, for example, three distinct 

 species were obtained, viz. Eurycope sarsii, E.fragilis, and Mun- 

 nopsis aiistralis. 



The wide range of certain species is of importance, Eurycope 

 fragilis ranges from Borneo in the north to near Kcrguelen, and 

 close to the antarctic ice-barrier in the south. Acanthocope spini- 

 cauda from Station 158 is representeJ off the west coast of Pata- 

 gonia by Acanthocope acutispina, which only differs slightly from it. 

 Tlie greatest depth which any Munnopsid is known to inhabit is 

 21 75 fathoms ; a single specimen of Euri/cope abijssicola was dredged 

 from this depth at Station 68 in the Atlantic. 



In my Report on the genus Serolis I pointed out that in Serolis 

 Bromleyana and S. antarctica, which have a comparatively wide 

 range, the individuals from the more southern localities are con- 

 siderably larger tlian those that inhabit the more northern latitudes. 

 This is strikingly shown in the case of Eurycope fragilis. The 

 more southern forms of this species are considerably larger than 

 the northern forms. 



Nearly all the species of Munnopsidse described by Sars and 

 others are of comparatively puny dimensions, the largest being 

 Eurycope giyantea, which attains the length of 33 millim. In 

 striking contrast are many of the specimens obtained from deep 

 water both in the northern and southern hemispheres by the ' Chal- 

 lenger ;' as instances, may be mentioned Eurycope pellucida, which 

 measures nearly 2 inches in length, and E. fntgilis, which measures 

 1| inch. In this group, as in so many others which are repre- 

 sented both in deep and shallow water, the deep-sea species attain to 

 the largest size. 



Several of the new species described in the present paper are 

 remarkable. Eurycope sjnnnsa is unique by reason of the great 

 development of spines upon the dorsal surface of the body ; this 

 character has not been met with in other Munnopsidse, which have 

 at most a covering of slender hairs, or a few spines, as in Eurycope 

 atluntica. The development of spines upon the body is a character 

 met with in other deep-sea Crustacea, though its meaning is not clear. 

 Another very remarkable species is the one which I have named 

 Eurycope pellucida. As its name implies, it is transparent, the 

 integument being thin and but little calcified ; the condition of the 

 specimen might naturally suggest that it had just changed its skin, 

 if a well-developed colony of Hydroids upon some of the segments 



