NOTES ON FISH OF THE CENUS DISCOG- 
NATHUS FROM INDIA AND PH RSEA, 
By N. ANNANDALE, D.Sc., F.A.S.B., Director, Zoological Survey 
of India. 
(With Plates IX—-XI.) 
Although it is only a few months since I published notes on 
the Indian species of this genus,! a large amount of additional 
material is already available and I have been able to examine 
living specimens in districts so far apart as Seistan in Eastern 
Persia and the Nilgiri Hills in Southern India. The latter district 
is particularly important as it is the type locality for several of 
the forms described by Jerdon and Day. It is not yet possible to 
clear up all the difficulties concerning the Indian species and much 
more material is still necessary before the Assamese and Burmese 
forms can be adequately discussed, but I hope that these notes 
may lead to further investigation of the genus, which is a particu- 
larly interesting one from a biological point of view. 
In my former notes I neglected to mention the species des- 
cribed by Tate Regan from the North Western Frontier of India 
under the name Discognathus wanae,* aud I gave no reference to 
the Persian form described by Berg as Garra persica.’ The latter 
is probably a local race of D. lamta, but the former seems to be a 
very distinct species. 
Two species from South India have been brought to my 
notice too late to be discussed in this paper. They will be des- 
cribed shortly by Mr. C. R. Narayan Rao under the names D. 
platycephalus and D. bicornutus. ‘These species must be attributed 
to Mr. Narayan Rao, but I have noted some of their more salient 
characters in the key to the species printed here. These charac- 
ters he has demonstrated to me. 
The genus as a whole falls into two sections, distinguished by 
the degree of differentiation of the adhesive disk behind the mouth 
on the ventral surface. Both these sections are found in Africa 
as well as in Asia and both extend into the Palaearctic part of the 
latter continent, but the most highly differentiated forms occur 
mainly in India and Malaysia, in which countries those with the 
simpler type of disk are practically absent. Among those in which 
the disk is best developed, a secondary differentiation occurs in 
1 Annandale, Rec. Ind. Mus. XVI, pp. 113, 129 (1919). 
* Tate Regan, Ann. Mag. Nat. Hist. (8) XIII, p. 263, fig. A (1914). 
3 Berg, Ann. Mus. Zool. St. Petersbourg XVIII, p. xi (1913). 
