DR. MARTIN BARRY ON THE CORPUSCLES OP THE BLOOD. 249 



Pig. 83. Outline of blood-corpuscles from the egg of the Duck, incubated about 

 12 days. 



Fig. 84. Blood-corpuscles, chiefly in outline, from the same egg. They are appa- 

 rently in a stage more advanced than those in the preceding figure, 

 with which, however, they were mixed. A nucleus, composed of discs, 

 has been represented in some of these ; and in one of the corpuscles, 

 discs are seen surrounding the nucleus. 



PLATE XXI. 



Fig. 85. Tadpole, about 5'". From the tail. Outline of epithelium-tables, having 

 essentially the same appearance as blood-corpuscles circulating in the 

 vessels of this larva. The peripheral portion of the six-sided tables 

 resembled that of the object fig. 89. 



Fig. 86. Tadpoles, about 5'". Epithelium-tables, from the tail, a, /3. Removed from 

 the lacerated edge of the tail, a Is in outline. The form and size 

 are here seen to have been very much the same as those of the blood- 

 corpuscle in this larva. The same remark applies to the interior of 

 this object, which is not shown in the figure. The envelope was also 

 membranous. |3. The germinal vesicle-like nucleus eccentric, and 

 scarcely coloured : the discs on the nucleus, blood-red. The other 

 objects in this figure were seen in situ, y Resembled /3, but it was 

 membranous at the surface. S, ^, g, ^, Resembled the ovum in their in- 

 terior, and were blood-red at the surface. 



Fig. 87. Tadpole, about 5'". From the tail. Outline of the appearance presented 

 by an epithelium-table undergoing division. (Dilute spirit.) 



Fig. 88. Tadpole, 6'". From the tail. Outline of three stages in the reproduction 

 of epithelium-tables, having a situation corresponding to that of the 

 large objects (centres) connected with pigment ramifications in figs. 90 

 and 91. The object on the left hand (in fig. 88.) represents the earliest, 

 and that on the right the most advanced, of these three stages. These 

 tables propagate by division, like every other disc. Each of the objects 

 in this figure consisted of two parts ; of which a was dark, — the other, 

 |3, colourless and pellucid, a. Oldest and largest tables ; |3, newest 

 and smallest tables, — mere discs. In the centre of ^, in the largest 

 object, there was seen a part still more pellucid. |3 Is not in the 

 centre of the object, but on one side. This corresponds with the situa- 

 tion of the most essential part in all other discs. In some instances, 

 the number of parts into which objects such as those in the present 

 figure were dividing, was observed to be four ; this having been a stage 

 still earlier. 



