HIGHER CRUSTACEA OF NEW YORK CITY 169 



Aeginella longicornis \\v. 



Aeginella longicornis Kroyor. 



Antennulae elongate, more than twice as long as antennae. 

 Mandibles with a palp. Second gnathopoda with two large teeth 

 on the palm. Body either smooth or thickly covered with short 

 slender spines. 



Fig- 39 Aeginella lo unicornis 



Length 10-25 mm. Color variahle. 



Large specimens taken among hydroids in Creat South bay. 

 Smaller ones were taken all along the bays among hydroids and 

 algae. 



Suborder b ISOPODA 



Arthrostraca with body flattened dorso-ventrally instead of later- 

 ally. The gills are borne on the abdominal appendages. 



The antennulae and antennae are much as in the Amphipoda, 

 the former with a peduncle of three, and the latter of five segments, 

 and a flagellum. Eyes composed of groups of ocelli and nearly 

 always sessile. The first thoracic appendage is a maxilliped, and 

 the next seven (occasionally only six) are walking legs and usually 

 all alike, whence the name Isopoda. or equal-footed. A part of the 

 basal joint, or coxa, of the leg is fused with the dorsal part of the 

 body and is known as the epimeron. A suture, known as the 

 epimeral suture, usually shows the line of fusion. The abdominal 

 segments are smaller than the thoracic and are frequently more or 

 less united. The first five bear delicate lamellar appendages which 

 function as breathing organs and the last pair are modified into 

 uropoda. 



Though not a large group, the members of the Isopoda are prob- 

 ably more widely distributed than anv other of the Crustacea. 



