A REVIEW OF THE MYSIDACEA 225 



apex ; the spines form a continuous series of about 70, 35 on each half 

 of the telson, without distinction between lateral and apical spines. 



Inner uropod more than iy 2 times as long as the telson, without 

 spines on its lower margin ; outer uropod about twice as long as the 

 telson. 



Pleopods of the male almost exactly the same as described by 

 Zimmer (1918) for M. gracile. Fourth pleopod (fig. 96, e) extending 

 beyond the distal end of the pleon, its terminal setae reaching to the 

 distal end of the telson ; endopod represented by a short simple lobe 

 with a single seta at the apex ; exopod very long and slender, 4- jointed, 

 the first joint much the longest, equal to the other three combined, 

 penultimate and ultimate joints each with a single long plumose seta, 

 that of the penultimate much the longer. 



Length of adult male and female specimens, 7 mm. 



Type lot. — From Cruz Bay, St. John, Virgin Islands. 



Occurrence. — Gui^f of Mexico: Carlos Stansch collector, 8 males, 

 3 females. West Indies (Virgin Islands) : Cruz Bay, St. John, 1896, 

 Chr. Lofting collector, 55 males, 76 females (type lot) ; Cruz Bay, St. 

 John, 1896, Ch. Levinsen collector, several hundreds of both sexes; 

 Water Island, St. Thomas, January 1896, Ch. Levinsen collector, 78 

 males, 91 females; St. Croix, February 21, 1906, Th. Mortensen col- 

 lector, 2 males, 1 female, 1 immature. 



Distribution. — M. integrum would appear to be an abundant species 

 in the Caribbean Sea area among the islands of the West Indies; it 

 likewise occurs in the Gulf of Mexico. 



Be?narks. — Except for the first lot, none of this material is in the 

 collection of the U. S. National Museum. The second is the type lot. 

 This new species is very closely allied to M. gracile (Dana) and differs 

 from it only in the shape of the telson. In M. gracile the apex of 

 the telson is emarginate so that it appears slightly bilobate, and the 

 number of spines on each half of the telson is about 25. M. integrum 

 has the apex of the telson entire without any trace of emargination, 

 with the result that the telson appears to be longer and narrower 

 than in M. gracile. There are 35 spines on each half of the telson. I 

 have examined hundreds of specimens of this new form and the telson 

 is similar in all of them. In its other characters it is almost exactly 

 the same as M. gracile, and Zimmer's figures of the latter will serve 

 almost as well for M. integrum. The other known species of the 

 genus, M. colmnbiae, is rather more distinct. The telson is incised 

 rather than emarginate at the apex so that the bilobate appearance 

 of the apex is more marked than in M. gracile. The antennal scale 

 is longer and narrower, 7 : 1 against 4 : 1 and 5:1. The fourth pleopod 

 of the male differs from that of both the other species in being rela- 

 tively shorter, in the larger endopod and in the fact that the exopod 



