ISOPODS OF NORTH AMERIOA. 



75 



segment long, lingulate in shi4)o, rounded posteriorly with crcnulate 

 margin. Outer branches of the uropoda arch over telson, but do 

 not meet in center; narrow, elongated. Inner branches of the uro- 

 poda extend beyond telson, are rounded posteriorly, and shorter 

 than peduncular joint; inner margins crenulate. Abdomen about 

 equal in length to fifth and sixth thoracic segments taken together. 

 First pair of gnathopods large, sul)- 

 chelate; second pair of gnathopods and 

 first pair of pereiopods subchelate, 

 small. Other pereiopods ambulatory, 

 slender. 



One specimen (type) sent by Mr. F. 

 Stearns to the U. S. National Museum 

 comes from between Nassau and 

 Andros Island, Bahamas. Another 

 specimen was taken by the U. S. 

 Bureau of Fisheries steamer Alhatro.ss off Cape Catoche, Yucatan 

 7'i/jje.—C'dt. No. 23900, U.S.N.M. 



F'(G. 60.— Cala- 



THUKA CRENU- 



LATA. First 



GNATHOPOD. 



•^Ki. (U.— A LATH II- 



ra crenui, ata. 

 Abdomen. 



17. Genus PARANTHURA Bate and West\A^ood. 



Segments of abdomen distinct in both sexes. First pair of antennse 

 have the Hagellum multiarticulato in both sexes. Second pair of 

 antenna^ in both sexes have a rudinientar}^ flagellum consisting of a 

 single article. 



Mouth parts as in CaJatlnira. 



ANALYTICAL KEY TO THE SPECIES OF THE GENUS PARANTHURA. 



a. Flagellum of first pair of antennte conaposed of nine articles. First three segments 

 of thorax of equal length; the three following subequal ami each one-third 

 shorter than either of first two. First five segments of alxlomen one-half the 

 length of seventh thoracic segment. Last abdominal segment funnel-shaped; 

 posterior margin coarsely denticulate and truncate. 



Paranthura mfundihulatn Richardson 

 a'. Flagellum of first pair of anteniiic composed of six to seven articles. First five 

 segments of thorax of equal length; sixth segment somewhat shorter than any 

 of preceding segments. First five segments of abdomen as long as seventh 

 thoracic segment. Last abdominal segment long and narrow, rectangular in 

 shape, with margins entire Fara)Uhuru rerrillii Richardson 



