[From the AmerioaxV Jouexal op Soiexoe and Arts, Vol. VII, Juxk, 1874 ] 



On a Neio Genus of Asellidce; by Oscar IIarger. — The. 

 presence of mandibular palpi has been hitherto regarded as a 

 character of the family of AselUdai, and is thus given by Dana 

 (U. S. Exploring Expedition, Crustacea, p. 714), and by Bate and 

 Westwood, in their late work on British Sessile-eyed Crustacea, 

 vol. ii, p. 313. This organ is present and well developed in Jara 

 copiosa, Asellodes cdta, and LhunoriaUgnorum^ marine species of 

 this family found on the coast of New England. It has been care- 

 fully figured by G. O. Sai'S (Hist. Nat. des Crustaces d'eau Douce 

 de Norvege, P livr. pi. viii) for Asellus aquaticus and occurs in 

 A. communis Say as well developed as in the European species, 

 but in A. tenax Smith, from Lake Superior, it is wanting. Tliis 

 species seems to be in all other respects closely related to the 

 genus Asellus, difiering from other species of that genus by char- 

 acters of specific value only. The most noticeable of these differ- 

 ences are the following : the antennulje have the third segment of 

 the peduncle small, short and similar to those of the flagellum ; 

 the ocelli are numerous as in A. communis ; the appendages of 

 the first abdominal segment in the females are subquadi'ant-shaped, 

 meeting each other along the median line, much as in A. comnnmis^ 

 instead of suljcircular and overlapping as in A. aquaticus. The 

 caudal stylets resemble those of A. aquaticus, as do also the feet 

 and the mouth parts, except in the absence of the mandibular 

 palpi, and on this character I propose for the species the new 

 generic name of Asellojjsis. — Comm,unicated by the Author. 



