APSET3DES. 145 



The first pair of legs are robust, terminated by a 

 strong didactyle hand. The second pair, though smaller 

 than the first, are more robust than the following, being 

 flattened and terminated by a broad hand-like joint, more 

 or less palmated, the penultimate joint (propodos), having 

 a small movable finger (dactylos) ; the five following pairs 

 of legs are slender and simple. The five segments of the 

 tail are short, but the last (sixth segment) is elongated, 

 and terminated by a rounded plate (the telson), on each 

 side of which is placed a flattened appendage, termi- 

 nated by one long and one short very slender filiform 

 branches, being the representatives of the last pair of 

 tail-feet. The five anterior segments of the tail are 

 respectively furnished with a pair of appendages, each 

 consisting of a basal stem supporting two delicate folia- 

 ceous plates strongly ciliated along their margins. The 

 eggs are borne in a semi-transparent pouch beneath the 

 breast, which extends from the second to the sixth 

 segment of the body. 



This is one of the most interesting genera of crus- 

 taceous animals. In some respects, such as the form 

 of the eyes, the articulated filament attached to the 

 upper-, the squamiform process of the lower- antennae, 

 and the cheliferous anterior feet, we perceive a relation- 

 ship to the macrourous stalk-eyed order of Crustacea; in 

 other conditions it assimilates the Amphipoda, in which 

 order Professor Milne Edwards was at the first disposed 

 to place it, although he subsequently referred it to the 

 Isopodes Idoteides (Encyclop. portatif. p. 182; Ann. Sci. 

 Nat. 1830, August), induced to this step by the struc- 

 ture of the breathing apparatus, which he attributed 

 to the under side of the segments of the tail ; whilst 

 the soldering of the head and first segment of the body, 

 and the podophthalmous structure of the eyes, induced 



VOL. II. L 



