1909.] Miscellanea. 291 



(i) According to Giinther there are three Indian species of 



Discognathus — 



Discognathus lamta. 



,, macrochir. 



, , nasutus. 



(2) According to Day there are also three, viz. — 



Discognathus lamta. 

 ,, jerdoni. 

 ,, nwdestus. 



One would, however, not be correct in imagining from this 

 that there are five distinct species of this genus, since Giinther, 

 writing in 1868, includes both of Da\^'s species lamta and jerdoni 

 (1867) in his lamta. He says: ''Having fortunately numerous 

 examples from the most distant localities, I have convinced myself 

 that they ought to be referred to a single species only." 



Apparently the chief points on which Day relies for the 

 separation of lamta and jerdoni are- — 



(i) The convexity or concavity of the interorbital space. 



(2) Ratio of length of head to total length. 



(3) The number of lateral transverse rows of scales, these 



being 4-4-I— 5 in lamta and 4^ — 2-| in jerdoni. 



With regard to the first two points Giinther sa^^s : " This species 

 {i.e., the lamta and jerdoni of Day combined) extends from Syria 

 to Assam, and, as ma^^ be expected in a species of so wide a range, 

 it is subject to some variation. " The points which Giinther takes 

 as subject to variation and therefore to be omitted as specific dis- 

 tinctions are just those which Day relies on as affording him firm 

 ground for such separation, Giinther writes: " The parts most 

 subject to variation are the snout with regard to form, width and 



prominence and the eye. " So that we have to fall back on 



the third of the above points, which at first sight seems of suffi- 

 cient importance to justify Day's distinction. 



Unfortunately there is no specimen of Day's Discognathus 

 jerdoniin the Indian Museum; apparently the only specimens of 

 this form were sent to the British Museum. There is, however, 

 a large number of D. lamta here, and in these the number of rows 

 of scales from the lateral line to the ventral fin ' is 3^ and not 5 as 

 Day states. This number is uniform in a large number of speci- 

 mens from widely different localities and is the number given for 

 modestus. 



Discognathtis modestus, Day, was first described in 1869 under 

 the name of Mayoa modesta, i.e., subsequently to the appearance of 

 Giinther's work. This so-called species is stated by Day to dift'er 

 from the others principally in — 



1 For Day's method of counting the L. tr. rows of scales, see Fauna of India 

 Fishes, vol. i, p. 6. 



