T909-] 
N. Ann AND ALE : Report on the Batoidei. 
9 
ten times as distant from one another at the base as they are at the tip of the saw. 
They frequently have the same number on the tw’o sides cf the saw. The posterior 
dorsal fin is usually rather larger than the anterior one. There is a narrow yel- 
lowish streak along the side of the saw in large individuals of this species, as there 
is in all adult specimens of P. pectinatus, but even in the males the colours 
are dull. 
D2iy says that P. zysron is perhaps more common in the seas of India than P. cns~ 
pidaHis, but this remark probably applies to the Arabian Sea rather than the Bay of 
Bengal. Several large specimens have, however, been taken by the Golden Crown.” 
The measurements of two males are as follows : — 
Total length (including saw) 
Length of saw 
Width of saw at base 
> j > > y ) ) y f-f P 
Breadth across pelvic fin 
456-0 cm 
127-9 - 
12-5 ,, 
6-25,, 
1.317 ,, 
462-5 cm 
120-0 ,, 
26-3 ,, 
12-5 ,, 
131-2 ,, 
The second of these .specimens has 28 pairs of rostral teeth, the first has 25 on one 
side and 26 on the other. I should not be surprised ultimately to obtain a series of 
specimens linking P. pectinains and P. zysron together. Undoubtedly there has been 
much confusion as regards the two species, and I am by no means satisfied that they 
are distinct. The large size of adult specimens and the difficulty with which they are 
preserved, however, militate against the acquisition of such a series. All the ordinär}^ 
specimens of P. pectinatus I have seen have been less than 10 feet long with the saw, 
while the two of P. zysron I have examined in detail have been over 15 feet. I doubt 
whether either form grows as large as P. perottetii. 
Family RHINOBATIDÆ) (Guitar-Fishes, Spear-Sharks). 
Shark-like rays (having the gills on the ventral surface) with the anterior part of the 
body depressed but comparative!}^ little expanded and the pectoral fin-rays not 
extending forwards to the sides of the head. The snout rounded or produced, 
without rostral teeth. No electric organ. Tw’o dorsal fins, wdthout spines. 
This family is divided by Günther, as by most other ichthyologists, into three 
genera, viz., Rhynchobatus , Rhinohatus and Trygonorhina. Trygonorhina, which is 
distinguished from Rhinohatus by having the anterior nasal valves confluent, is only 
known from the S. Pacific, but Rhynchobatus and Rhinohatus are both well represented 
in Indian seas. Two very dissimilar species, how-ever, are held by most authors to 
constitute the former genus, although they differ from one another considerably not 
only in the shape of the snout but also in the structure of the head. These two species 
, are R. ancylostonnis and R. djeddensis. The former in my opinion is not congeneric 
with the latter and as Gill’s generic name Rhamphobatis is available for it, I have placed 
it in that genus. As regards R. djeddensis, moreover, I have been confronted with a 
difficulty in the matter of the proper genus to which it should be as.signed. It is sup- 
posed to be distinguished from the species of Rhinohatus by certain rather ill-defined 
