No. 26.] ARTHROSTRACA OF CONNECTICUT. 237 



The following description is from Miss Richardson's Mono- 

 graph on the Isopods of North America. 



" Head deeply set in thorax ; anterior margin straight ; poste- 

 rior margin rounded. Eyes wanting. Ovarian bosses present on 

 the first four segments of the thorax at the anterior part of the 

 sub-lateral margin ; epimera evident as narrow plates lateral to 

 the ovarian bosses. The epimera occupy the entire lateral mar- 

 gins on the last three segments. The segments of the abdomen 

 are distinct. The terminal segment is broad, more or less bilobed. 

 The pleopoda consist of five pairs of double-branched latnellar 

 appendages, closely crowded together on the ventral side of the 

 abdomen. 



" The five pairs of incubatory lamellae surround a large open 

 area normally filled with eggs. The first pair have the terminal 

 lobe of the distal segment large, well defined, and incurved. 



"All the legs have a high quadrangularly shaped expansion or 

 carina on the basis. 



" Male with all the segments of the thorax distinct, and with 

 the lateral margins contiguous. First four segments of the 

 abdomen well defined at the sides, but fused in the middle of the 

 dorsal surface. The last two segments form a single large piece, 

 the fused terminal segment being indicated only by a small median 

 point on the posterior margin. The body is a little more than 

 twice as long as wide. Eyes are present. The rudimentary 

 pleopoda are pairs of small oval processes, one pair on each 

 abdominal segment. The abdomen is about one and a half times 

 as broad as long." 



This species is parasitic on Palcemonetes vulgaris (a prawn) 

 and has been reported from New Hampshire to Florida; East 

 Providence, Rhode Island ; Acushnet River, Massachusetts ; Bald- 

 win Ledge, Mississippi ; Brooklyn, New York. 



ONISCOIDEA. 



Body more or less depressed, oval or oblong in form, in some 

 cases capable of being rolled into a ball. Head generally small 

 and more or less sunk into first segment of thorax, no true 

 rostral projection. 



First antennae always of very small size, never composed of 

 more than three segments, the last of these being often rudimen- 



