304 
Part III. — Eighth Annual Report 
The Sandy Ray (R. circularis). As previously stated, the purses of this 
species are very like those of Selachians. When fresh, they are of an 
amber-brown colour, and translucent, or almost transparent. When they 
have lain in sea- water, the colour deepens, but the translucency remains. 
A flattened side of the purse, so characteristic of those of the other 
four species, is not obvious. The purse is curved somewhat in a S-shaped 
fashion, and its walls are composed of finer horny fibres than those of the 
other species. 
The purse of the skate may be described as composed of a body, which 
at each end is prolonged into a pair of hollow horns. The purse of the 
sandy ray does not possess strings for its attachment, nor are the horns 
drawn out into long filaments for this purpose, as those of the Selachian 
purse. The body of the purse is about 2^ inches long and If inches broad. 
The horns are a pair of short ones (1 \ inches long) at the lower or 
first formed end of the purses, and a pair of much longer ones (4 inches 
in length) at the upper end. 
The usual small apertures leading into the cavity of the horn are found 
on the inner side of the tips of the horns. Unlike those of sharks, the 
filamentous ends of the horns are not coiled in the form of a spiral thread, 
nor do they approach anything like the length of the spiral thread of the 
shark purse, where they exceed several feet. 
The Starr?/ Ray (R. radiata). The purse of this form is the smallest 
of the five. It is always quite flat on one side, and strongly convex on 
the other. The embryo is usually found under the flattened side of the 
purse.* Unlike the egg-case of the preceding form, the purse of the 
starry ray is quite opaque. It is composed of coarsely beaded fibres of a 
deep olive green colour, inclining to black. The whole purse, including 
horns, measures some 4| inches. Of this length about 2 inches goes to 
the body of the purse, i.e., to the part containing the egg. This part of 
the egg-case is slightly over If inches broad at its widest portion, and 
about half an inch thick at the centre or point of greatest convexity. The 
lower horns are rather more than 1 inch long and the upper ones exceed 
\ \ inches. 
The lateral margins of the purse are somewhat flattened at the seam, 
as in that of R. clavata, and a few fixing filaments are usually present 
near the lower end. They are, however, very rudimentary in this and 
the other forms, except R. batis. The yolk of the egg is very small, and 
not more than f of an inch in diameter ; it is usually of a beautiful rosy 
colour. 
The Blue Skate (R. batis). The egg-case of this species exceeds that 
of any of the others very much in size and weight. When freshly taken 
from the oviduct of the mother-skate, the purse is of a greenish yellow 
colour, which after exposure to sea-water for some time darkens to a dull 
olive-green, and finally becomes almost black. Its extreme length is fully 
9 inches, with a breadth of 3^ to 3J iuches, and at the point of greatest 
convexity the purse is about an inch thick. The egg-case is built up 
of less coarsely beaded fibres than that of the starry ray. As in the 
other forms, the lower end of the purse is closed in a crescent-shaped 
fashion, the upper and last-closed end being more squarely rounded off. 
The horns of the two ends project inwardly. They are snorter in pro- 
portion than those of the starry ray, projecting beyond the body of the 
purse at the lower end for about 1J inches. The upper horns are rather 
shorter, about an inch in length, and somewhat twisted or curled. On 
* Because the yolk sac turns more easily to the position of stable equilibrium, 
i.e.j with the embryo uppermost, when the curved surface of the purse is on the 
under side. 
