ISOPODS OF NORTH AMERICA. 



291 



EXOSPHiEROMA YUCATANUM (Richardson). 

 Sphperoma yucalanum Richakixson, I'roc. U.S.Nat. Mus., XXIII, 1901, p. 584. 



LoeaUty. — Cape Catoche, Yucatan, 

 Dej^th.—M fathoni.s. 



Head tran.sverse; eyes .situated at the extrcMue post-lateral angles. 

 First pair of auteiinte short, reaching the posterior 

 margin of the head; flagellum six-jointed. Second 

 pair of antiMHKO, with a flagellum composed of ten 

 joints, extend to the posterior margin of tlie second 

 thoracdc segment. 



First thoracic segmctit longer tiian an^- of the 

 following segments, its post-lateral angles produced. 

 The remaining segments of equal length; epimera 

 produced laterally into acute processes. 

 First abdominal segment witii suture lines. Last segment termi- 

 nating posteriorly in an obtuse point, on either side of which is a small 

 tooth. The base of the segment bears three low tu])ei'clcs, one in the 

 median line and one on either side. The uropoda are short, not reach- 



Fl(i. 305.— KxoHPH.K- 



ROMA YUCATANrM. 



Abdomkx. 



Fig. 30t).— Exo.sru.KiioMA yi cai' amm. d. M ax ii.lii'K.I). x 



(DlAliliAMMATIC. ) 



/), FKDNTAI, LAMINA AND CI.YPEl'S. 



ing the post-latei"al teeth. Both branches are ecpial in length and 

 width, the outer branch pointed, the inner branch truncate. 



Surface of bod}'^ smooth; color bluish. 



One specimen was taken at Cape Catoche, Yucatan. 



Ti/pe.— Cat. No. 23905, U.S.N.M. 



