PEREZ FARFANTE: AMERICAN SOLENOCERII) SHRIMPS 



length of dorsal flagellum to length of carapace in 

 North American shrimp ranging from about 1.15 

 in 10-mm cl individuals to about 0.95 in 23-mm cl 

 shrimp. In Bahamian and southern populations, 

 ratio decreasing from about 0.95 in shrimp 10 mm 

 cl to about 0.6 in shrimp 24 mm cl. Scaphocerite 

 not reaching distal margin of antennular pedun- 

 cle or exceeding it by as much as 0.1 of its own 

 length; lateral rib ending distally in long spine, 

 usually extending to level of distal margin of 

 lamella; antennal flagellum at least 3.5 times 

 total length of shrimp: 1 10-mm tl female with 

 flagellum 385 mm long (measurements taken by 

 me of specimen caught south of Great Inagua, 

 Bahama Islands, in 311 m, at Oregon II stn 

 10849). Third maxilliped usually exceeding an- 

 tennular peduncle by length of dactyl, occasion- 

 ally surpassing it by length of dactyl and as much 

 as 0.2 that of propodus; length of dactyl about 

 0.75 that of propodus. 



First pereopod, stoutest of five, reaching at most 

 distal end of carpocerite. Second pereopod sur- 

 passing carpocerite by length of dactyl or by entire 

 length of propodus. Third pereopod exceeding an- 

 tennular peduncle by 0.6 to entire length of pro- 

 podus. Fourth pereopod overreaching carpocerite 

 by 0.5 or more length of dactyl. Fifth pereopod, 

 longest of five, exceeding antennular peduncle by 

 length of dactyl or by latter and as much as 0.2 

 length of propodus. Order of pereopods in terms 

 of their maximal anterior extensions: first and 

 fourth, second, third and fifth. First pereopod 

 with long, strongly pointed spines on basis and 

 ischium; second pereopod with long sharp spine 



FIGURE 57. — Mesopenaeus tropicalis, ? 25 mm cl, off Key Largo, 



Fla. Eye. 



FIGURE 58. — Mesopenaeus tropicalis, 2 20 mm cl, west of Light 

 House Reef, Belize. A, Mandible. B, First maxilliped. c, Arthro- 

 branchia. c\ Enlargement of c (all from left sidel. 



on basis. In female, coxa of third pereopod pro- 

 duced into plate extending mesially, then 

 uniquely folded ventrolaterally; coxa of fourth 

 pereopod produced in strong plate resembling 

 head of bird, "beak" consisting of long, sharp 

 spiniform projection directed posteriorly, entire 

 plate curving around lateral horn on plate of 

 sternite XIII; coxa of fifth pereopod bearing short 

 plate produced anteromesially in blunt projection. 

 In male, coxa of fourth pereopod with short plate 

 bearing small anterior tooth; fifth pereopod with 

 large subtriangular tooth on anterior margin. 



Abdomen with sharp, high, middorsal carina 

 from third to sixth somites; low, rounded, some- 

 times barely perceptible carina on second somite 

 in larger specimens; posterodorsal margin of third 

 through fifth somites with median incision; sixth 

 somite with small, sharp spine at posterior end 

 of carina, and pair of small spines postero- 

 ventrally. Telson with median sulcus deep an- 

 teriorly and penetrated posteriorly by longitud- 



335 



