132 TANAIDiE. 



ISOPODA. TANAIDuE. 



ABSRRANTIA. 



Genus— LEPTOCHELIA. 



Leptochelia. Dana, U.S. Explor. Exped. p. 800. 



Tanais, pars. Kroyer, Nat. Tidssk. vol. iv. Lilljeborg, Bidrag till Kiln- 

 nedomen orn de inom Sverige och Norrige forekommande 

 Crust, af Isopod. underord. och Tanaid. fam. p. 25. 



Generic character'. Animal long and slender. First segment 

 of pereion fused with cephalon, the following six segments sub- 

 equal. Pleon consisting of six separate segments. Eyes pe- 

 dunculated. Superior antennse long, and terminating in an 

 articulated flagellum. Inferior antennae very short. First pair 

 of gnathopoda long and chelate ; " fingers slender and gaping" 

 (Dana); second pair slender, feeble, and terminating in a long 

 styliform dactylos. The five pairs of pereiopoda subequal in 

 length, the three posterior pairs having the bases somewhat 

 more robust than the two anterior pairs. Pleopoda, five an- 

 terior pairs, biramose ; posterior pair unibranched and multi- 

 articulate. 



This interesting genus holds an intermediate position 

 between Tanais and Paratanais. It agrees with the 

 former in the general contour of the body, and with the 

 latter in the form of the second pair of gnathopoda as 

 well as of the pereiopoda. The pleon has five distinct 

 segments, each carrying a pair of pleopoda, as in Pai'a- 

 tanais, but it has only a single branch to the caudal pair 

 of pleopoda attached to the sixth segment. The an- 

 tennae are somewhat abnormal, since there is no distin- 

 guishable peduncle. The superior pair have the first 

 joint long and robust, the second not half as long as the 

 preceding, the third and every successive joint is still 

 shorter than the preceding, so that unless the first two 

 joints of the peduncle be fused together, it is difficult to 



