156 A. Alcock — Carcinologicul Fauna of Indih. [Xo. 2, 



male on the one hand, and the female and yonng male on the other hand, is found 

 in the second and third abdominal terga : in all adult males the third abdominal 

 tergam is very strongly carinated transversely, and the second is carinated also, 

 but not nearly so strongly : in all adult females both the second and the third terga 

 are either equally strongly carinate, or, if one is more prominent than the other, it 

 is the second. 



The other differences between the sexes are those (emphasized by Miers) that 

 occur in the sculpture of the hand and fingers ; and these differences also apply 

 between the adnlt male and the young male, which Miers does not appear to have 

 taken into consideration. 



The nine species separated by Miers can, in my opinion, be reduced to three, 

 namely, M. banksii Leach (Itumph's species), M. victor, Fabr., and M. lunaris Hbst. 

 Hilgendorf. 



The next paper to be referred to is that by Hilgendorf (Monatsber. Ak. Berl. 

 1878 [1879] p. 810), which is a most authoritative contribution, since the writer had 

 been able to examine Fabricius ' types of M. victor and M. planipes, and apparently 

 also Herbst's specimens. Dr. Hilgendorf states definitely (1) that if. victor Fabr. 

 is the species carefully described and figured as M. victrix by Miers (loc. cit.) ■ (2) 

 that the species figured by Herbst. on pi. xlviii. fig. 6 is the unequivocally recogniz- 

 able M. rubro-lineata of Miers {loc. cit.) ; and (3) that the M. planipes of Fabricius 

 is if. lunaris of Herbst. It is most unfortunate that Dr. Hilgendorf does not tell us 

 whether both of Herbst's figures refer to the same species, or not. We now know, 

 without any ambiguity, what Herbst's pi. xlviii. fig. 6 is ; but we are still in doubt 

 as to the meaning of pi. vi. fig. 44*. 



The last reference necessary is to de Man's paper (Notes Leyden Mas. III. 18S1, 

 p. 109), on the species of Matuta in the Leyden Museum, a paper that embodies the 

 results of an examination of no less than 270 specimens. With most of Dr. de Man's 

 synonomy I entirely agree, although I am unable to follow him in the acceptance of 

 M. granulosa, M. maculata and M. picta as distinct species. 



Dr. de Man rightly recognizes the value of the sculpture of the hand and 

 fingers in the descrimination of the species ; but, equally with Mr. Miers, he takes 

 no due notice of the fact that this character varies with age, at any rate in the male 

 sex. He considers that the development of the tubercles on the surface and lateral 

 margins of the carapace furnishes a character of only secondary importance, in 

 which opinion I cannot quite agree with him if he includes the tubercle on the 

 postero-lateral border. 



It remains only to refer to the opinions of those who, like M. A. Milne-Edwards 

 and Dr. Ortmann, regard all the forms of Matuta as varieties of a single species. 

 This view would seem to imply that the characters by which the species are usually 

 recognized are variable, — either indefinitely so, or in response to some local 

 peculiarities of the environment. Of this I can find no evidence. 



Certain of the characters that I have used in separating the species in the 

 Indian Museum Collection are, as far as an examination of over 400 specimens goes, 

 perfectly well defined, whether in the young or in the adult, and whether from the 

 same locality or not. 



The characters of the first importance in the separation of the 

 species are those emphasized by Milne Edwards, namely (1) the form 

 of the carpus of the penultimate pair of legs — whether full and 



