e,e,2 



BULLETTN n4, FNTTED STATES TSTATTOTSTAL MUSEUM. 



Terminal .segment of abdomen very short, usually triangular. Outer 

 branch of all the pleopoda furnished with trachea'. Uropoda extend- 

 ing- beyond the terminal a])d()nnnal segment; the basal article large, 

 triangular, entire; the outer branch small, rather slender, inserted at the 

 inner post-lateral angle of the basal article; outer 

 branch long, rather slender, a little compressed.^' 



ANALYTICAL KEY TO THE SPECIES OF THE (iENCS SPH.ERONISCUS. 



a. Body smooth. Terminal segment of abdomen broad and 

 posteriorly rounded, not constricted. First thoracic seg- 

 ment without distinct coxopodites. 



Sphieroniscns portoricenxia Richardson 

 a^. Body covered with little transverse rugse. Terminal seg- 

 ment of abdomen strongly constricted in the middle 

 and somewhat enlarged toward the outer border. First 

 thoracic segment with a tooth-like lobe on the sides 

 anteriorly (coxopodites?). 



Spk,'troniscuf< racalmam Upen^u ( Bilimek ) 



SPHiERONISCUS PORTORICENSIS Richardson. 



Fig. 703.— Sph.eroniscus 

 portork'ensis. «, ab- 

 DOMEN. ''. Uropoda 

 (INSIDE). 



Spliuruniscus portoriceii.sis Richardson, Proc. U. S. Nat. 

 Mus., XXIII, 1901, p. 573. 



Locality. — El Yunque, Porto Rico, at an altitude of 2,800 feet. 



Body oblong, very convex, con- 

 tractile into a ball. Surface per- 

 fectly smooth. Head set in first 

 thoracic segment; front straight; 

 epistoma forming a triangular 

 shield. Eyes very small. An- 

 tenna' with tlagellum composed 

 of three joints. 



First thoracic segment twice 

 as long as head, and longer than 

 any of the other segments. Cox- 

 opodites not distinct from seg- 

 ment. 



First two abdominal segments 

 with the lateral parts concealed, 

 the three following ones con- 

 tinuing the outline of the body. 

 The terminal segment is twice as 

 broad as long, very short, widely 

 rounded posteriorly. The basal 

 joints of the uropoda are large, 



Fig. 704.— SPH.ERONiscrs portoricensis. a, second 



MA.XILLA. K 51f. 6, MA.XILLIPED. X 27^. fi, 



Outer lamella of first maxilla, x 51 |. d. 

 Inner l.\.mella of .same.?' x 51f. f, Mandible. 



X 27i. 



«SeeBudde-Lnnd for cliaracters of genus, Crustacea Isopoda Terrestria, 1885, pp. 

 44-45. 



&This species differs from all the other Arniadillidid;!' in liaving the inner lobe of 

 the first maxill.M> armed with three plumose ijrocesses instead <if two. 

 med several specimens and find that they agree in this characti'r. 



I have exam- 



