58 ME. E. J. MIEES ON THE IDOTEIDJS. 



The single example, in dry state, in the collection is unfortu- 

 nately without any definite locality. 



In its widely-separated and laterally-projecting epimera it is 

 very unlike any other sj)ecies of the genus with which I am ac- 

 quainted, M. Lucas, indeed, in his figure of /. algirica, exhibits 

 a somewhat similar structure of the epimera, but the figure is 

 probably exaggerated. I. alf/irica, moreover, has a 3-jointed 

 postabdomen and a truncated terminal segment ; and I have con- 

 sidered it synonymous with I. onetallica on the authority of 

 specimens in the Paris collection. 



ly. JPostaMomen with all the segments (in a dorsal view) consoli- 

 dated and forming a single inece. (Leptosoma, Hisso ; Cra- 

 byzos, /S'. Bate.) 



The species of this section may be distinguished as follows : — 

 a. Terminal segment not emarginate at its distal end. 



Suboblong, with straight subparallel sides ; terminal segment 

 subacute : epimera of the second to fourth segments not dis- 

 tinguishable ; head with a dorsal tubercle. 



1. I. carinata, Lucas. 



Suboblong; sides and thoracic segments straight; terminal 

 segment subtriangulate at distal end : epimera all distinct ; head 

 without a dorsal tubercle. 2. I. stricta; Dana. 



Narrow; lateral margins of the thoracic segments angulated ; 

 terminal segment acute or subacute: epimera very small; 

 head without a dorsal tubercle. 3. I. acuminata (Leach). 



Very narrow and elongated; sides of thoracic segments straight ; 

 terminal segment produced and acuminated : epimera very small ; 

 head without a dorsal tubercle. 4. I. longicaudata (S. Bate). 



b. Terminal segment emarginate at its distal end. 

 Obloug-ovate : epimera distinct and well "developed ; head with 

 a dorsal tubercle. 5. I. LicMensteinii, Krauss. 



Idotea caeinata. 



Idotea carinata, Lucas, Anim, artic, in Expl. Sci. Algerie, i. Cr. p. 60, 

 pi. vi. fig. 1 (1849). 



Body oblong-oval, moderately elongated, strongly carinated in 

 the middle dorsal line. Head with the anterior margin distinctly 

 excavated, the antero-lateral angles nearly right angles ; the upper 

 surface armed with a strong tubercle, which is more or less di- 



