424 Mr. A. Alcock on 
§ 5. The Nature of the Secretion. 
The amount of secretion available for examination was so 
small—only about a fluid drachm, including débris of tropho- 
nemata—that no satisfactory results have been obtained. 
The capture was at a distance from the ship, and to guard 
against putrefaction the secretion was removed and bottled 
and covered with strong (rectified) spirit. By the action of 
the spirit it was at once coagulated. 
When fresh it looked like custard, or, rather, like thin pus ; 
it was viscid, had a sticky greasy feel, and a heavy sweetish 
meaty smell. Prolonged heat at 212° Fahr. leaves a trans- 
lucent horny cake (albumin). Fresh Fehling’s solution gave 
no reaction (no sugar), but the quantity tested was so small 
that the inference must be quite uncertain. A greasy white 
film (probably fat) was left wherever the secretion touched 
the bottle. 
A portion of the clot macerated in water, stained in car- 
mine, and examined in glycerine, shows an abundance of 
formed elements. Besides epithelium, which may perhaps 
be adventitious, there are to be seen crowds of round granular 
cells of a uniform diameter of about 3559 of an inch. Of 
these some, though quite transparent, possess no nucleus at 
all, fewer others have two or more nuclei, while the great 
majority have a single small excentric nucleus. There are 
also to be observed free nuclei. 
In the Mahdnadi specimen the secretion, which was abun- 
dant glairy and turbid, was tested only for albumin, and 
coagulated in lumps when heated. 
The secretion thus seems to vary; and it may be men- 
tioned that in Pteroplatea micrura—a viviparous fish allied 
to the Trygons, and one which carries its young in the same 
way—the secretion changes with the advance of gestation. 
As to the nature of the secretion, then, all that can at 
present be predicated is that it is very rich in albumin and 
that it contains a remarkably large proportion of corpuscles 
and nuclei. 
§ 6. The Fetus of Trygon Bleeker. 
On removing the foetus we are first attracted by the large 
size of the spiracles, which are full of the creamy uterine 
secretion. 
It may perhaps be of advantage to recall the fact that the 
spiracles are the first pair of branchial clefts, which, in many 
