Boone, Crustacea, Cruises of "Eagle" and "Ara," 1921-28 141 



Material examined : Three large specimens from Havana, Cuba, 

 March 27, 1926, taken by the "Ara." 



Color : Mr. Vanderbilt 's field notes state that this shrimp is ' * slaty 

 olive-grey in color when alive." 



Technical description : Carapace robust, comprising exactly one- 

 third of body-length, exclusive of rostrum ; rostrum beyond the cara- 

 pace two-fifths as long as the carapace, continued posteriorly for 

 one-third the length of the carapace, armed on the upper surface 

 with nine teeth, the most posterior one of which is well back on the 

 carapace and twice as far from the next tooth as the latter is from 

 the next tooth ; the eighth and ninth teeth are very close to each 

 other, and the ninth tooth is very close to the apex of the rostrum, 

 which is acute and forward-directed. There are five weaker but well 

 developed teeth on the inferior rostral margin, subequally spaced 

 along the convex median portion of the rostrum. There is an approxi- 

 mately median longitudinal carina on each lateral face of the rostrum, 

 which is continuous posteriorly with the orbital margin. The antennal 

 spine is short, acute, and a short distance posterior to it on the cara- 

 pace there is another acute spine, in line with and subequal to the 

 first antennal spine. A light, short groove runs obliquely just below 

 these two spines for one-third the length of the carapace. The lateral 

 and posterior margins are carinate. 



The abdomen is robust, moderately compressed laterally. The six 

 segments and caudal fan have about the same proportions and contour 

 as do those of M. olfersi and M. jamaicense. 



The eyes are of moderate size, spherical, terminal, black ; the cornea 

 of slightly greater diameter than the stalk. 



The inner antennae have the basal article longer than the eye, 

 excavate beneath the eye; the outer lateral margin thickened and 

 terminating subdistally in an acute spine; the second and third 

 articles are short, cylindrical, successively narrower ; the second arti- 

 cle is ciliated along both lower margins. The flagellum is two- 

 branched, the inner whip single, multiarticulate, 140 mm, long; the 

 outer whip biramose, its outer branch being the longest and thickest, 

 156 mm. long; the shorter whip is only two-fifths as long as the 

 associated one. The external antennae have the proximal joint short, 

 strong, with an acute spine at the outer distal angle ; the scaphocerite 

 is a little longer than the rostrum and has the outer lateral margin 

 thickened and armed distally with an acute spine; the distal margin 

 is widely, evenly rounded and ciliate and the inner margin is also 



