MACRURA. SCHMITT. 



361 



b. Dactyl of third or external maxilliped of adult male 

 from one and one-half to two and three-fourth times 

 the length of the propodus. Rostral crest high but 

 not forming a decided triangle. 



indicus var. penicillatus, Alcock. 



The distinction of true Peneus indicus from its near 

 relatives and varietal forms is by no means satisfactory. 

 De Man, 42 in saying that "in young individuals both of 

 P. indicus [longirostris] 43 and of P. merguiensis the 

 rostrum projects beyond the autennal scales and is more 

 or less conspicuously curved upward, in many cases these 

 young specimens may, however, be distinguished by the 

 teeth of the upper margin, which in P. merguiensis 

 usually occur till near the tip, while in P. indicus 

 [longirostris} the foremost tooth is situated opposite the 

 terminal joint of the anteunular peduncle, so that the 

 distal unarmed part of the upper border appears com- 

 paratively longer," seems to leave the typical form of 

 P. indicus without its younger stages, especially as he 

 cites both Alcock's figure 44 of the juvenile and his own 45 

 in illustration of his remarks. Can it be that Alcock had 

 no young forms of typical P. indicus, and that the lone 

 specimen which Pesta 46 had with an indicus-like rostrum, 

 but short, is the true young of P. indicus f Nevertheless 

 one feels that Kemp 47 is nearer the correct solution of 

 the difficulty when he says "the variety longirostris 

 described by de Man, is based entirely on the length of 

 the rostrum and the great degree of variation that Indian 

 specimens exhibit in this respect leads me to believe that 

 the varietal name cannot be retained." Stebbiug, 48 how- 

 ever, more recently, in spite of admitting, in connection 

 with the possible relation of the species to "Palcemon 

 longlcornis," Olivier, 49 that "Its great variability, 

 explained by Alcock and de Man, makes the study of 

 it rather perplexing. Especially the elongation and 

 slenderness of the rostrum in the younger and smaller 

 specimens give them a very different appearance from 



42 "Siboga" Bxped., xxxixo, Decapoda, pt. i., Pensefdse, 1911, p. 105. 



4 ' ! De Man, though he does not use the varietal name lonyirostris 

 in the immediate quotation given here, has reference only to the 

 variety, as is shown by the citation in his "Siboga" Report ; cf. foot- 

 note above. 



44 Cat. Indian Decapod Crust., 1906, pt. Hi., fasc. i., pi. i., fig. So. 



45 In Max Weber's Zool. Ergebn., ii., 1892, pi. xxix., fig. 53. 

 "'Archiv f. Naturg., 1915, Abt. A., Heft 1, p. 117. 



47 Mem. Indian Mus., v., 1915, No. iii., p. 319. 

 4S Ann. Durban Mus., i., 1917, pt. v., p. 4 45. 

 4 Encycl. Meth., viii., 1811, p. 662. 









