LYSIANASS1DES. 71 



AMPHIPODA. LYSIANASSIDES. 



NATATORIA. 



Subfamily LYSIANASSIDES. 



Superior antennae very short, with the base dilated and 

 suddenly tapering. Coxae of the four anterior pairs of 

 appendages very deep, the fourth not broader than the 

 preceding. One pair of gnathopoda very slender, and 

 imperfectly developed. 



In this subfamily the animals may readily be distin- 

 guished by their general form. They are not much 

 compressed, but the anterior coxae are deep enough to 

 hide the limbs attached to them. The superior antennae 

 are always very short and pyriform, the shortness com- 

 monly resulting from the second and third joints of the 

 peduncle being almost rudimentary, while the flagellum 

 is seldom longer than the peduncle. The first or second 

 pair of limbs are generally short and strong, whilst the 

 other is slender and feeble. In some genera it is the 

 first, whilst in others it is the second, which is strong. 

 We therefore propose to divide them into 



a. Those genera which have the first pair of limbs 

 robust, and the second pair feeble. 



b. Those that have the first pair of limbs slender, 

 and the second strong. 



