410 M. A. Boeck on the Amjyhipoda 



parts of the mouth are on the whole not so strongly elongated 

 as in the preceding. The mandibles are likewise toothed and 

 bipartite at the apex ; but here there is a small trace of a mas- 

 ticatory tubercle, which is deficient in the preceding genus, 

 but becomes strongly developed in the following genera. The 

 third joint of the palpi is much abbreviated; the outer lamella 

 of the first pair of maxilla3 is of the same form, but shorter 

 and broader than in Acanthonotus ; the inner lamella is con- 

 siderably smaller, and furnished with a far smaller number 

 (eight to ten) of hairs, in this resembling that of the next 

 genus. The palpi, which in Acanthonotus were thin, shorter 

 than the outer lamella, and had their joints of nearly equal 

 length, become in this and the following genera broader and 

 longer, with the first joint very short ; the maxillipedes in 

 Iphimedia resemble in form those of Acanthonotus^ but the 

 fourth joint of the palpi is much more strongly developed ; the 

 first pair of feet are much elongated, which is especially due 

 to the length of the second joint ; the fifth joint, which is 

 slender, has the inferior hinder angle produced into a process 

 which meets the claw, and thereby forms a small two-fingered 

 hand ; the second pair of legs, which in Acanthonotus were 

 strong and short, become in this genus much elongated and 

 of the same form as in the genus Anoni/x ; in the next genus 

 both hands become converted into distinct prehensile organs. 



Acanthosoma, Owen. — The characters upon which Gwen 

 established this genus were so unsatisfactory that Kroyer 

 combined it with the genus Amjihithoe ', and this view has 

 since been always followed. But I think that there are rea- 

 sons for reviving it. A. Costa's Ejjimeria, of which one spe- 

 cies occurs on our coast, may be combined with it. I have 

 already, whilst describing the preceding genus, cited the pe- 

 culiarities in the structure of this which have led me to adopt 

 it ; and the two species hystrix^ Owen, which is found on the 

 coast of Finmark, and parasitica^ Sars, from the coast of 

 Bergen and Farsund, which will probably coincide with A. 

 [Ejnmeria] tricristata, Costa, may be placed under it, although 

 in some particulars they differ from each other. 



Family 3. Corophiidse, Dana. — I have already treated of 

 the characters of this family under the Gammaridaj. It in- 

 cludes a great number of forms, which, however, difier com- 

 paratively little from each other, and some of which show 

 great agreement with the Gammarida?, whilst others approach 

 the Caprellida?. 



Fociocero2)sis, mihi. — In this genus the body is somewhat 

 depressed, the epimera small, the antennte long and slender, 

 the superior inserted far in front of the inferior, at the apex of 



