176 The University Science Btlletin. 



A. Propodus of first pair of legs armed witli one or more triangular processes. 



B. Propodus of first pair of legs armed with a triangular process near 

 the distal end and with a long spine at the proximal extremity. 

 Uropods about one-half the length of terminal abdominal segment. 

 Outer branch three-fourths as long as inner, which equals the 

 peduncle in length. C. nickajackennis Pack. 



BB. Propodus of first pair of legs armed with two triangular processes. 



C. Propodus with three additional short processes. Uropods 

 about as long as terminal abdominal segment. Outer branch 

 two-thirds as long as inner, which is two-thirds as long as 

 jieduncle. C. stygia Pack. 



CC. Propodus with three additional spines not jjrocesses. Uropods 



a little longer than terminal abdominal segment. Outer 



branch about one-half as long as inner, which is two-thirds 



as long as peduncle. C. alabamohsis Stafford. 



BBB. Projjodus of first jjair of legs armed with three triangular processes. 



C. tridentata, sp. nov. 



AA. Propodus of first pair of legs not armed with triangular processes, but 

 edged inside with spines. 



B. First pair of antenna\ with flagellum composed of eleven articles, 

 extend one-third the length of the fifth article of the peduncle 

 of the second antenna. Second antenna longer than the body; 

 flagellum composed of about eighty-six articles. 



C. richardsonce Hay. 

 BB. Fii-st pair of antennae, with flagellum composed of five articles, 

 extend half the length of the peduncle of the .second antenna. 

 Second pair of antennae "probably as long as body," flagellum com- 

 posed of "at least forty segments." C . smithsii Ulrich. 



Coecidotea tridentata sp. nov. 



(Plate XV.) 



Size. The bod.\' without the antennae and uiopoda measures in length from 

 9 mm. to 19 mm. and in width from 1% mm. to 3 mm. The length of the 

 body is approximately five or s-'x t ines the width. This species is much larger 

 than the others of this genus that have been describsd. From the descriptions 

 I infer that 10 mm. is about the maximum of (*. styi/ia Packard, the largest 

 member of the genus, while 3 mm. is supposed to be the maximum of C. 

 smithsii Ulrich, the smallest. These figures suggest that the smallest mature 

 C. triden'ata are about the size of some of the members of other species, but 

 the laigpst indi\iduals are fully double that size. 



Color. The color is chalky white, the body wall being sufficiently clear 

 to show the dark food canal within. Material .stored in alcohol appears very 

 [lale yellowish gray. 



Stmchire. Head: Narrower than first thoracic segment. Wider than long. 

 The cephalic margin narrower than the caudal, somewhat concave, and bear- 

 ing the antennules and antennae, the bases of the latter appearing veiy heavy 

 when compared with the size of the head. The antennule consists of the 

 basal segments and a flagellum of from twelve to eighteen segments, the two 

 parts of about equal length; the basal segment stoutest, a trifle longer than 

 twice its width; second segment two-thirds as broad as basal and about 

 .same length; third segment much smaller; five-eighths as broad and one- 

 half as long as second. Its distal end bears the tai)ering flagellum. The an- 



