ME. E. J. MIEES OUT THE IDOTEID/E. 61 



very slender, siibequal. The epimera (iu a dorsal view) are very 

 small, and in tlie second to fourth segments occupy the middle 

 of the lateral margins ; in the fifth and sixth segments they are 

 placed near to, and in the seventh segment qnite at the postero- 

 lateral angle of the segment ; in the last two segments they are 

 of nearly triaugular form. The terminal plates of the operculum 

 are considerably longer than broad, and rounded at their distal 

 ends. Length of the largest example iu the Museum collection 

 about 1 inch (25 millim.), breadth rather less than 5 inch 

 (5 millim.). 



This is a very variable species, and I have been obliged to unite 

 under one name several types that have usually been considered 

 distinct. 



It occurs on the shores of the Mediterranean and Adriatic, in 

 the Black Sea, on the south British coasts, and northward ap- 

 parently as far as the island of Cumbray ou the Clyde. 



Dr. Leach's designation of I. acuminata may apply to what 

 may be considered the typical form of this species, in which the 

 body is less distinctly carinated, the epimera less distinctly 

 angulated, and the terminal segment lanceolate, with the sides 

 rounding off to the distal extremity, which is acute or subacute, 

 but not produced and acuminated. 



Besides Leach's typical specimen (which is in very bad con- 

 dition), there is but a single specimen, from Tripoli, in the British- 

 Museum collection presenting these characters. 



In the Paris collection I have examined five exam])les from 

 Nice (types of Milne-Edwards' s description of /. appendiciclata, 

 Risso) ; also a good series from Algeria without special locality 

 (M. Lucas), designated I. angustata ; and three from the neigh- 

 bourhood of Constautine (M. Lucas), labelled /. cainto, Kathke. 



Idotea acuminata, var. lancieoemis, Misso ? 



This variety nearly resembles the typical acuminata, but the 

 terminal segment is angulated, not rounded on the sides towards 

 the distal extremity, which thus appears more or less triangulate. 



Two specimens from Marseilles and one from Dalmatia (Dr. 

 Heckel), in the British-Museum collection, belong here. 



Idotea acuminata, var. appendiculata, JRisso. 

 Under this designation may be grouped the specimens having 

 the body more depressed, flattened on the sides, but strongly 



