280 



CAEL BOVALLIUS, AMPHIPODA HYPERIIDEA. I. 2. 



HYPERIIDJE. 



Euthemisto. 



= Euthemisto Gaudichaudii, F. E. Guerin. 

 = Euthemisto antarctica, Dana. 

 = Euthemisto compressa, A. Goes. 



Themisto Gaudichaudii, F. E. Guerin, 

 Euthemisto Thomsoni, Stebbing, 

 Themisto antarctica, Dana, 

 Themisto Guerinii, Spence Bate, 

 Themisto compressa, A. Goes, 

 Themisto bispinosa, A. Boeck, 



And lastly Euthemisto australis, Stebbing, which is a little doubtful, seemingly 

 very closely allied to, if not identical with, Euthemisto antarctica. 



Euthemisto Gaudichaudii, in the sense it is taken here, and E. compressa 

 are closely related, and agree in many characteristics as well as in general form of body. 



The reasons for the synonymy adopted here will be given under the heads of the 

 corresponding species. 



The characteristics which have been found of value for distinguishing the species 

 in the genus are not many, they are: 



1. The femur of the last three pairs of peraeopoda being broad — or comparatively narrow. 



2. The lower hind corner of the tibia in the fifth pair of peraeopoda being more or less 

 produced downwards. 



3. The dactylus of the fifth pair of peraeopoda being provided with spine-like teeth on 

 the front margin — or not. 



4. The first pair of uropoda reaching beyond the apex of the second — or not. 



5. The relation between the telson and the peduncle of the last pair of uropoda. 



A. The femur of the last two pairs of peraeopoda is dilated, being about twice as 



long as broad. The first pair of uropoda reach beyond the apex of the 

 second pair. The telson is fully a third part as long as the peduncle of the 

 last pair of uropoda 1. E. Hbellula. 



B. The femur of the last two pairs of peraeopoda is comparatively narrow, being 



about three times as long as broad. 

 I) 1. The first pair of uropoda reach beyond the apex of the second pair. 



bb 1. The inner margin of the inner ramus in the third pair of uropoda 



is smooth ._ 2. E. antarctica. 



bb 2. The inner margin of the inner ramus in the third pair of uro- 

 poda is pectinated _ 3. E. australis. 



b. 2. The first pair of uropoda do not attain the apex of the second pair. 



bb 3. The telson is broader than, and more than a fifth part as long 



as, the peduncle of the last pair of peraeopoda 4. E. Gauilicuamlii. 



bb 4. The telson is narrower than, and less than a fifth part as long 



as, the peduncle of the last pair of uropoda 5. E. compressa. 



