294 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



the extremity of the abdomen by some little distance. The outer 

 branch is the shorter and is broadty rounded posteriorly. The inner 

 branch is more pointed at the extremity. 



Five individuals of this species were sent by Mr. Heath from Mon- 

 terey Bay, California. 



Type.C&t. No. 22574, U.S.N.M. 



EXOSPH^EROMA THERMOPHILUM (Richardson). 



X)>1i:rr<i>n<i tlirrnio/iltiltiiii RICHARDSON, Proc. U. S. Nat. Mns., XX, 1897, pp. 465- 

 466; Amer. Naturalist, XXXIV, 1900, p. 223. 



Locality. New Mexico, near Socorro, in a warm spring. 

 Head nearly three times as broad as long, with its anterior margin 

 widely rounded. Eyes round and post-laterally situated. The first 

 pair of antenna?, with a flagellum of eight articles, 

 extend to the middle of the first thoracic seg- 

 ment. The second pair of antennae reach the pos- 

 terior margin of the first thoracic segment; the 

 flagellum consists of eleven articles. 



The thoracic segments are all similar with the 

 exception of the first, which extend.- late rail J T 

 around the head, almost touching the peduncle 

 of the first pair of anten- 

 na? with its anterior angle. 

 The epimeral parts are 

 continuous with the seg- 

 ments, with no indication 

 of a separation from them. 

 The abdomen is formed 

 of two distinct segments, 

 the first of which is partly 

 covered by the last thoracic segment, the sec- 

 ond is subtriangular, rounded posteriori} 7 . 

 The internal lamella of the uropods is moder- 

 ately broad, well rounded, and extends to the 

 posterior edge of the last abdominal segment, 

 is half as long and half as broad as the internal one, and is more pointed 

 at its extremity. 



The body is oblong-ovate with almost parallel sides. Its surface 

 is entirely smooth. 



The grayish-brown color of the body is everywhere marked with 

 small black spots and lines, which run together, forming a broad, black 

 band in the center of each one of the thoracic segments. All the 

 exposed edges of the body are tinged with a bright orange. 



This species can readily be distinguished from Exosphseroma dugezi, 

 to which it is closely related, by the absence of hairs on the body, 



FIG. 311. EXOSPH^ROMA 

 THERMOPHILUM. X 4|. 



FlG. 312. EXOSPH-EROMA THER- 



MOPHILVM. MAXILLIPED. x 

 38 j. 



The external lamella 



