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V. The Blood- corpuscle considered in its different Phases of Development in the 
Animal Series. Memoir ll.—Invertebrata. By T. Wharton Jones, F.R.S . , Lec- 
turer on Anatomy, Physiology and Pathology, at the Charing-Cross Hospital, 8§c. 
Received May 8, — Read June 19, 1845. 
THE invertebrate animals, of which I am here about to consider the blood-corpuscle 
in its different phases of development, are some of the more readily procurable 
examples of the divisions Annulosa and Mollusca. The order in which I purpose to 
proceed is from the higher to the lower classes of each division, an order the contrary 
of that adopted in the case of the Vertebrata. 
Annulosa. 
1. My examples of Annulosa are from the classes of Crustacea, Arachnida, Insecta, 
and Annelida. 
Examination of the Blood- corpuscles of Crustacea. 
2. As examples of Crustacea I have taken Crabs and Lobsters. 
Blood-corpuscles of Crabs. 
3. By snipping off the end of one of the legs of a Crab, the blood flows freely out 
from the stump, and is thus readily obtained*. A small quantity of the blood being 
received on a plate of glass direct from the animal, and forthwith examined under 
the microscope, it is seen to contain a very considerable number of corpuscles. 
4. Kinds of Corpuscles. — Both granule-cells and nucleated cells, — the latter the 
more numerous, — may be distinctly recognised. 
5. Shape of the Cells. — If very great expedition has been employed in receiving the 
blood as it flows from the animal on the plate of glass, spreading it out and trans- 
ferring it to the microscope for examination, the granule-cells may be seen to be of 
an elongated oval shape, the nucleated cells spindle-shaped (figs. 1 and 6.). These 
shapes however are speedily changed. 
6. As regards the granule-cell, it tends to become circular (figs. 2 and 3.), but it 
* The blood as it flows from the animal appears of a pale reddish gray or neutral tint ; when collected in a 
watch-glass, it separates into a spongy-looking mass and a serous fluid. This spongy-looking mass, which is 
of a slight pink colour, consists principally of the corpuscles aggregated, there being little spontaneously coa- 
gulable material in the plasma to form a true clot. The serous fluid, which is bluish by reflected light, and 
reddish by transmitted light, is coagulated by heat, and also by. acetic acid. 
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