ISOPODS OF NORTH AMERICA. 



669 



the .second; the fourth is e(|iiiil in len^tli to the second; the Hfth is 

 twice us long us the t'oiii'th. 'Vhv tlsinclluin is coini)()sc(l of two h)no-, 

 siihe([Ual articles. The second :niteiin;e extend to the posterior maro-in 

 of the first thoi'acic segment. 



TIk^ first se^'nient ot" the thorax is u little hMi^ci' than any of the 

 following- .seg'ments. and has the 

 {intero-latcral angles produced 

 forward to surround the head, 

 and the post-lateral angles pro- 

 duced backward. The epiniera 

 are not distinct in atiy of the 

 .segments. 



The first two segments of the 

 at)doiuen have the lateral part.s 

 covered bv the seventh thoracic 

 seo'ment. The three following 

 segments continue the oval out- 

 line of the body. The .sixth or 

 terminal segment is sub-ti"iangu- 

 lar, with sides a little concave 

 atul apex rounded. The basal 

 segment or peduncle of the ui'o- 

 poda is not visible in a dorsal 

 view. It is large and somewhat 



([uadrate. The outer branch occupies all the .space betwe<Mi the lateral 

 part of the fifth abdominal segment and the terminal abdominal seg- 

 ment. The outer branch is broad posteriorly and well rounded. The 

 inner branch extends to the extremity of the outer branch and to 

 the extremity of the abdomen. 



All the legs are ainl)ulat()ry in character. 



121. Genus UROPODIAS Richardson. 



Head with th(^ front produced in a ])rominent rounded -lobe. Eye.s 

 small, obscure. Extei'nal antenna', with a fiagidliun of two joints, the 

 second joint the smaller of the two. 



First six thoracic segments with the lateral parts lamellarly expanded. 

 Seventh segment as long as the six preceding segments, but with the 

 lateral parts unchneloped, and not wider than the first two aljdominal 

 .segments, which likewise have the lateral parts or epimeral plates 

 undeveloped. 



Abdomen not narrower than the thorax, the lateral parts of the 

 third, fourth, and fifth segments being expanded and contiiuiing 

 the regular outline of the body. The abdominal segments e([ual in 

 length and half as long as th(> thoracic segnuMits. Terminal segment 

 (piadi-angular in shape, the posterior margin i)roduced in ;i medium 



•'Hi. 70,S.— AKMADILUDIUM yUADRlKRONS. (l, HEAD. 



■ 14J. /), Last two segments of abdomen with 

 rp.opoDA. ,■- 14^. 



