294 



BTTLLETIN 54, UNITED STATES NATIONAL MUSEUM. 



the oxtreniity of tho abdomen )>y some little (listance. The ontei' 

 branch is the shortei" tiiul is broadly 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. 



%>r^— Cat. No. 225T4, U.S.N.M. 



EXOSPH/EROMA THERMOPHILUM (Richardson). 



Sphxrotiia OieruiopliUiiin Kiciiakdson, Proc. U. S. Nat. IVIus., XX, 1897, pp. 465- 

 466; Amer. Naturalist, XXXIV, 1900, p. 228. 



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

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

 widely roiuided. Eyes round and post-laterally situated. The tir.st 

 pair of antennae, with a flagellum of eight articles, 

 extend to the middle of the tirst thoracic seg- 

 ment. The second pair of antemui? reach the pos- 

 terior margin of the iirst thoracic segment; the 

 tiagellum consists of eleven articles. 



The thoracic segments are all similar with the 

 exception of the first, which extend." lateral!}' 

 around the head, almost touching tiie peduncle 

 of the tirst 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 ])artly 

 covered by the last thoracic segment, the sec- 

 ond is subtriangular, rounded posteriorly. 

 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 Exoxph»ro)na diu/ext., 

 to which it is closelv nd:ited, by the absence of hairs on th(> body, 



Fig. 311. — Exo.sph^:rom.^ 

 thermophilum. x 44. 



Fig. 312.— Exosph.brom.a. ther- 

 mophiu'm. m.\.xii,i,iped. x 



The external lamella 



