PHILOSOPHICAL TRANSACTIONS 
IV. The Blood-corpuscle considered in its different Phases of Development in the Animal 
Series. Memoir I. — Vertehrata. By T. Wharton Jones, F.R.S., Lecturer on 
Anatomy, Physiology and Pathology, at the Charing-Cross Hospital, 8$c. 
Received February 27, — Read June 19, 1845. 
Part I. 
THE mode in which I purpose to treat this part of my subject, is to trace the blood- 
corpuscle in its different phases of development in the vertebrate series, from the lower 
to the higher classes. 
I commence therefore with the blood-corpuscle of the Skate, taken as an example 
of the lowest class. 
Examination of the Blood-corpuscles of the Skate. 
1. There are in the blood of the Skate two kinds of corpuscles, which at first 
view, under the microscope, especially attract the notice of the observer : the one 
kind is without colour, but appears dark in consequence of refracting the light 
strongly, is of a roundish form, and about x sV dtb of an inch in diameter, or even 
larger ; the other kind, which is more numerous, is of a red colour and oval form, 
and measures about T iV oth of an inch long, by ixVo th of an inch broad (figs. 1, 2 a, 
3 , and 7-)* 
2. Structure of the first-mentioned kind of Corpuscle . — The first-mentioned kind of 
corpuscle is composed of an agglomeration of granules surrounded by a cell-mem- 
brane. The granules are clear and strongly refract the light. They measure about 
2 o,o o c) th of an inch in diameter, but it is to be remarked, that they may at one time 
appear separate, and at another time more or less fused together, as if they had been 
granules of quicksilver. 
3 . In consequence of the structure, so far as it has been described, of the cor- 
puscle under consideration, I propose to designate it by the name of granule blood-cell. 
4 . On one side of this granule blood-cell, a clear spot may sometimes be seen, 
indicating the place of a nucleus (fig. 1.). 
MDCCCXLVI. K 
