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foot-jaws and are armed with a slender spine at the base; fintrers one and a half as lone as 

 the palm. Of the following legs that seem to be unarmed at base, the y^ extend to the middle 

 of the terminal joint of the outer foot-jaws, almost just as far as the more slender legs of the 

 5"^ pair that reach but very little farther. The dactyli of the 4'i> pair measure three-fourths the 

 length of the propodi and the propodi are little more than half as long as the carpal joints. 

 The dactyli of the 5"^ pair are just half as long as the propodi; the carpi (4,4 mm.) are almost 

 twice as long as the propodi (2,5 mm.). 



The exopod of the 5"^ pair is a litde smaller than those of the other legs. 



The thelycum consists 1° of a posterior plate that is flattened on its outer surface and deeply 

 notched anteriorly, 2" of a nearly semicircular, slightly concave, anterior plate, that terminates 

 anteriorly in a sharp median tooth. The thelycum shows therefore in the middle a concavity. 



Parapenaeopsis Hungerfordi Alcock from Hongkong differs by a much longer rostrum, 

 by the stronger carination of the abdomen, by the form of the thelycum etc. 



Penaeus Fabr. 



The genus Penaeics Fabr. comprises at present about 20 species, 4 or 5 of which, 

 however, are probably synonyms, besides 4 varieties; they are distributed through the Indopacific 

 and the Adantic, while one species occurs in the Mediterranean. The majority of the species 

 are found in the tropical and subtropical seas. 



P. caraiiwte Risso inhabits the Adriatic and the Mediterranean, but occurs also on the 

 west coast of Portugal and Spain and on the west coast of Africa, this species being known 

 from Benguella. It is doubtful whether P. caramotc occurs also on the south coast of England. 

 Besides P. caramote, only two other species are found in the Atlantic. P. brasilie^isis Latr. 

 occurs along the east coast of America from New York to Brazil, but also in the east Atlantic: 

 it has been observed at Whydah, St. Thome, off the coa.st of Dahomey, Elmina and even in 

 the lake Aheme, that is situated 15 kilom. distant from the sea, with which it is in commu- 

 nication by a river. A variety aztcciis Ives is known from Vera Cruz. The other, P. setiferus]^., 

 is distributed along the east coast of the United States, being known from Charleston, through 

 the West Indies, to Brazil ; it is often observed in large numbers at the mouth of the rivers 

 of Florida. 



About a dozen of species are found in the Indopacific. P. canaliculahis, described by 

 Olivier one century ago in the Encyclopedic methodique, constitutes with P. drasiliensis and 

 three other indopacific species a section of the genus, in which the post-rostral carina is grooved 

 and reaches almost to the posterior margin of the carapace, while the lateral rostral grooves 

 extend just as far backward. P. canaliailahis and P. drasiliensis differ, however, from the 

 three others by the telson bearing no lateral spinules. This P. canaliculatus is distributed from 

 the Fiji Islands to the Gulf of Tedjourah near the Red Sea and is one of the 7 species that 

 were taken by the "Siboga". Two other species of this section, viz. P.japonicus Sp. Bate and 

 P. latisulcatus Kish., range from Japan to the Red Sea and both have been taken by the 

 "Siboga" at various Stations; P . japonicus occurs also at the Fiji Islands and at Dar-es-Salaam, 



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