342 
MR. J. DALRYMPLE’S DESCRIPTION OF AN INFUSORY 
seconds. Soon afterwards he attached himself to another very young female and, 
remained so attached seventy seconds. Could discern this latter connexion of the 
end of the sperm-tube with the side of the female very distinctly. 
“ 4 p.M. — Saw in the trough, by the aid of the microscope with a one-inch achromatic 
object-glass, a conjunction of a male with a female. On approaching the female the 
male attached himself by the sperm-tube to her side, and remained so attached 
nearly a minute. Saw this most clearly, but owing to the movement of the animals 
in the water it is almost impossible to see more than that there is a distinct adhesion. 
“ Most of the above observations were made with a single lens only, of two inches 
focus, and the others with the microscope.” 
So acute an observer as Mr. Brightwell could not possibly have been mistaken 
in the fact so repeatedly observed, and it leaves us therefore in no doubt as to the 
dioecious character of this singular family ; but there is another circumstance con- 
nected with the anatomy of the male, so curious as possibly to be unique. The male 
I have said possesses the same general figure as the female, it has also the contractile 
vesicle, which I have ventured to name the respiratory sac (Plate XXXIV. fig. 12 
D C), as well as the fibres furnished with the vibratory or ciliated tags, subservient 
to the office of a circulation. It has also the ordinary rotiferous apparatus at the 
head, through the agency of which its various movements of locomotion are performed ; 
the pink eye (Plate XXXIV. fig. 12 B) is distinct. It has however no mandibles, 
no pharynx, oesophagus, pancreatic glands or stomach ; there appear to be no organs 
of prehension, deglutition, digestion or assimilation. At the lower part of the 
animal, on the other side of, and opposite to the valvular opening, are three small 
oval bodies (Plate XXXIV. fig. 12 H), massed together, having no communications by 
tube or otherwise, but fixed in their place by short ligaments, that may be rudiments 
of a stomach. 
They are not testes, for they have no communications with the sperm-bag, and they 
do not exist in the female. I have therefore provisionally regarded them as the 
rudiments of a digestive apparatus. 
The difference of sex in these two forms is plainly evidenced by the fact, not only 
of the difference of structure, the presence of active spermatozoa in the male, but by 
the observed fact of the intromission of the male organ into the vaginal canal of 
the female. That the male animal is produced by the female and developed within 
the ovisac in the same manner as the female embryo, is also proved by many observa- 
tions ; and one of the drawings of the male has been made from a specimen stiU in 
the interior of the parent, and even at that period having its sperm-bag filled with 
active spermatozoa. 
Thus this animal is not androgynous, and a careful reconsideration of the whole 
family of Hydatina is desirable to determine whether this law prevails in this exten- 
sive group of infusory animalcules. Had the male not been traced ah ovo, or had it 
been met with apart from female specimens in the water, it had been taken for a 
