NO. 2 MUD SHRIMPS SCHMITT 9 



CALLIANASSA JAMAICENSE, n. sp. 



Lineae thalassinicae present ; central dorsal " oval " area bounded 

 posteriorly by the cervical groove, and delimited before by a trans- 

 verse groove behind the rostrum ; cervical groove crosses the carapace 

 two-sevenths of the length of the carapace from its hinder margin ; 

 the groove crossing the carapace behind the rostrum is about one- 

 seventh the length of the carapace behind the tip of the rostrum; the 

 rostrum extends beyond a line joining the barely marked, obsolescent 

 lateral angles of the front by about half this distance. The rostrum is 

 a stout conical spine reaching about as far forward as the distal margin 

 of the cornea. 



The eyestalks are contiguous throughout the extent of their inner 

 margins; on the inner margin just in advance of the centrally placed 

 cornea there is the suggestion of a tubercle reminiscent of the one 

 described by Holmes ^' for his LepidophtJialmus , now Callianassa 

 (Callichirus) eiscni from Lower California, a species to which the 

 present one shows kinship, yet from which it may readily be dis- 

 tinguished by the proportions and armature of the major cheliped. 

 The eyestalks of C. jamaicense fall a little short of the first segment 

 of the antennular peduncle ; the second segment of the antennular 

 peduncle is very little longer than the first measured from the orbital 

 margin of the carapace, and a little short of a third of the length of 

 the third segment ; the terminal segment of the antennal peduncle 

 reaches the middle of the last segment of the antennular peduncle, the 

 fourth segment a little past the second of the antennular peduncle, and 

 the second antennal segment and the first or basal antennular segment 

 reach about equally far forward ; the antennal scale is represented by a 

 small, inconspicuous spine at the antero-lateral angle of the second 

 segment ; the first or basal segment reaches about to the middle of the 

 cornea ; as in all these Callianassas, the third segment of the antennal 

 peduncle in dorsal view scarcely appears to be more than an articulation 

 between the second and fourth segments of the normally five-seg- 

 mented peduncle ; the third segment is for the most part behind and 

 hidden by the second segment. 



The ischium of the larger right cheliped is nearly equal to the upper 

 border of the palm in length and a little (about one-fifth) shorter than 

 the merus ; upper border of merus a little longer than that of carpus ; 

 merus about one and three-fourths times as long as its median width ; 

 carpus at middle of its length about as wide as length of upper border ; 



" Proc. California Acad. Sci., ser. 3, Zool., vol. 3, no. 12, p. 311, pi. 35, figs. 

 6-13, 1904. 



