TO INDIAN CARCINOLOGY. 117 



to that genus, as restricted by Pi'of. S. J. Smith ; most of the species are prol)ably 

 referable to ParapencBtis, Smith, which is characterized chiefly by the absence of 

 branchiae from the last thoracic segment *. A revision of the Penscida^, based on a 

 large collection both of shallow-water and deep-water forms, is much needed, for at 

 present the genera are in a state of considerable confusion, and Spence Bate appears to 

 have worked independently of the results previously arrived at by Smith. Too much 

 stress has perhaps been laid on certain features of the branchial arrangement, as, for 

 instance, the number of epipodites. in drawing up generic characters. 



269. Pen^us monodon, Fabr. 



P. monodon (Fabr.), Bate, 'Challenger' Macrura, p. 2r>(), pi. xxxiv. fig. 1 (1888). 



{ = !'■ semisulcatus, De llaan). 



Bombay, Madras, Ganjam, many specimens (JMy) ; very common on the Soutli 

 Indian coast and the chief edible species (J. i?. IT.). 



The rostrum is about equal to the antenual peduncles, though sometimes longer, and 

 is continued as a sulcate I'idge almost to the hind margin of the carapace ; the tootli- 



formiila is ^^-^, with usually three teeth below. Th(> antennular flagella are about 



equal in length to the peduncle. A short longitudinal ridge occurs on the carapace 

 below the hepatic spine, and parallel to the fri'e margin. The basal joint of the first 

 legs is bispinose, that of the second legs unispinose. The fourth, fifth, and sixth 

 abdominal segments are carina ted. The species reaches a length of about a foot. 

 P. tahitensis, Ileller, and P. carinattis, Dana, are perhaps referable to this species. 



Distribution. From the Red Sea and K. Africa to Japan, Australia, and the Pacific 

 (Fijis). 



270. Pen^tjs iNDicus, Milne-Edw. 



/'. iiidicm (Milne-Edw.), Bate, 'Challenger' Macrura, p. 219, pi. xxxiii. fig. 2 (1888). 



(=/'. mcrgitiensis, De Man). 



Kurachi, Madras, Ganjam, Calcutta, Akyab, many specimens {Lay) ; very common at 

 Madras {J. B. H.). 



The rostrum is styliform distally, and \ aries consideralily in length ; in young 

 examples it is usually considerably longer than the antennular peduncles, whereas in 

 adults it is generally shorter than in the young, and is continued as a prominent crest to 



~ y 



about the middle of the carapace ; the tooth-formula is 7^-_-., with, as a rule, four to six 



small teeth below . On the carapace the rostrum forms a faint and obscurely sulcate ridge 

 posteriorly, which, however, does not reach the hind margin. The antennular flagella 



* The genus Metapenctuis, Wood-Mason (,Anu. Mag. xNat. Kisl. ser. G, vol. viii. p. 271, IS'Jl), is .separated from 

 ParajHua-us by vei^ alight characters, the most important of which is the presence of a rudimentary anterior 

 arthrobianch on the penultimate thoracic segment, a character which is absent in one of the species referred by 

 Wood-JIason to the genus. 



63* 



