1917.] S- Kemp : Notes on Crustacea Decapoda. 51 



In several of these localities the species was undoubtedly 

 obtained in brackish water, the lowest specific gravity of which I 

 have a definite record being i'ooi5 (corrected) in the case of 

 certain specimens from the Tale Sap. On the other hand the 

 records from Coconada, Green I. and the Mergui Archipelago indi- 

 cate that the species also occurs in the open sea near land. 



A. indicus was found in company with A. japonicus in the 

 Tale Sap and in the I\tergui Archipelago, and with A erythraeus at 

 Ennur. 



The distribution of the species^ as far as at present known, 

 may be summarised as, — Bombay, Bay of Bengal and Gulf of 

 Siam. The characters mentioned by Milne-Edwards being insuffi- 

 cient to determine the species with any exactitude, the records by 

 Dana, Walker, Henderson and Pearson are open to doubt. Even 

 if accepted, they would not indicate any marked increase in our 

 knowledge of the distribution of the species. 



Acetes erythraeus, Nobili. 

 (Text-figs, jc-e, 2b, 3b, 4b, $a,d, yb.) 



igos- Aceies erytliraeus, Nobili, Bull. Miis. d' Hist, naf., Pcifi's, p. T,g4, te\t- 



fig. I. 

 igo6. Acetes erytJiraeus. Nobili, Ann. Sci . imf.. Paris (9), IV, p. 23, p!. i, 



figs. 5^ 5«-/- 



The eyes are not quite so long as in /I. indicus, being only 

 about one-third the length of the carapace ; the stalk is also 

 stouter and, proportionately to the length of the cornea, rather 

 shorter. 



The basal segment of the antennular peduncle of the female is 

 about 1-3 times the length of the two terminal segments combined ; 

 the second segment is decidedly stouter than in A . indicus, the length 

 being not more than 2^ times the greatest breadth ; the third segment 

 is from 4 to 4^ times as long as wide (text-fig. i^). In males a well- 

 marked dimorphism appears to exist in respect of the proportions of 

 the peduncular segments. In four small males from Penang, other- 

 wise practically indistinguishable from the rest of the specimens in 

 the collection, the ultimate segment is greatly elongated, precisely 

 as in A. indicus. The second segment in these examples is about 3 

 times as long as broad, while the third is longer than the first and 

 about 9J times as long as broad (text-fig. le). All the other males 

 in the collection dift'er widely from the Penang individuals and 

 from the males of any of the other three species, the antennular 

 peduncle bearing a close resemblance to that of the female. In 

 such specimens the basal segment is from it to i"3 times the 

 length of the two following, the second segment is from 2 to 2^ 

 times and the third from 4 to nearly 5 times as long as broad 

 (text-fig. ic). 



The outer antennular flagellum of the male closely resemble 

 that of A. indicus, and possesses only one clasping spine; the two 

 basal segments are, however, shorter. In the males from Penang 



