28 
Memoirs of the Indian Mnsenni. 
[VOL. II, 
Skin tough. The scales flat and more or less rounded, diflering greatly in size on 
different parts of the head and body, to which they are confined on the disk ; 
the largest occurring in a small patch behind the shoulder girdle ; those between 
the eyes and on the middle of the posterior part of the back and the base of the 
tail larger than those on the central part of disk, where they are so small and so 
deeply sunk in the skin that they are almost invisible in the fresh specimen ; the 
tail completely covered with flat scales except as regards the ventral surface of 
the part anterior to the spine ; this surface, the pectoral and pelvic fins bare. 
Mouth small ; the jaws distinctly but not strongly undulated. The teeth white, 
with a single distinct central transverse ridge, larger on the upper jaw at the sides 
than in the middle, not occupying the whole of the exposed surface of either jaw. 
Two individuals were taken in a seine-net at Puri on March 21st during a .short 
visit to the Orissa coast made by Dr. Jenkins and myself. One had already been cut 
up before the specimen could be secured, but the other (a female) has been preserved. 
It is the type of the species, and is numbered F in the books of the Indian Museum. 
This ray is distinguished from T. jenkinsii by its flat scales, by its proportions, 
and by its coloration. The difference as regards the last point is not, however, ver}^ 
marked, for the pale spots are faint and soon disappear in preserved specimens, while 
the coloration of the ventral surface was perhaps due to some extent to suffused blood. 
From T. gerrardii, T. alcockii is distinguished by its larger size, shorter and stouter 
tail, and diff'erently proportioned disk, as well as by the fact that its spots are scattered 
on the anterior as well as the posterior part of the body. 
As regards the processes on the floor of the mouth in T. alcockii, I am not in a 
position to give a description of their normal characters, because in the one specimen I 
have examined they are markedly asymmetrical. I may say, however, that there 
are, in this specimen, four blunt processes situated at about equal distances from one 
another. One of them is much longer than the others. 
The D^pe of the species was certainly mature and had probably just given birth 
to a young one as the nutritive filaments in one uterus were highly developed. 
Trygon jenkinsii, sp. nov. 
Size moderately large (adult male 10375 mm. across the disk). 
Disk considerably broader than long. The pectoral angles rounded ; the length 
from the greatest diameter to the tip of the snout 2^ times in the length of the 
disk. The snout sharply pointed, not much produced, longer than the distance 
between the eyes, which are large and prominent ; the length of the snout con- 
tained 3^^ to 4 times in the length of the disk. 
Tail c^dindrical throughout, without a trace of a cutaneous fin, not much longer than 
the disk is broad, sometimes bearing two serrated spines, which are long and slender 
Colour. — Dorsal surface reddish olive, becoming paler at the edge of the fins, 
without definite markings. The tail dark grey , mottled on the ventral surface 
with brown and white at the base. The ventral surface of the disk dead creamy 
white. 
