184 M. Jules Kiinckel on the existence of 
. Prare XIII. 
Fig. 1. Cytheridea spinulosa, from left side. 
Fig. 2. The same, from above. 40 
Fig. 3. The same, from below. F 
Fug. 4. The same, from front. 
Fig. 5. The same, hinge-margins. 4 
Fig. 6. The same, ventral contact margins. ; 
Fig. 7. Cythere plana, left valve, from side. —_) 
Fg. 8. The same, from above. 
Fig. 9. Pontocypris Davisoni, from left side. 
Fig. 10. The same, from below. 
Fig. 11. Loxoconcha Lilljeborgu, from left side. ;- x 40. 
Fig. 12. The same, from above. 
Fig. 13. The same, from below. 
Fig. 14. The same, from front. 
Fug. 15, The same, from behind. 3) 
XVIIL.— On the existence of Capillary Arterial Vessels in In- 
sects. By JULES KUNCKEL*. 
ZooLoGists supposed that the circulation of the blood in insects 
was limited to certain currents detected by Carus in transparent 
larvee, when in 1847 M. Blanchard proved that the trachez of 
these animals fulfilled the function of arteries, by conveying, 
in a peripheral space, the nutritive fluids to all the organs. 
He ascertained, by means of delicate injections, the existence 
of a free space between the two membranes composing the 
trachez: the injected fluid expelled the blood and replaced it. 
After having verified and confirmed M. Blanchard’s discovery, 
M. Agassiz insisted upon the evidence of the demonstration. 
Seeking afterwards to complete this discovery, he paid parti- 
cular attention to the termination of the tracheee. In a memoir 
published in 1849+, this naturalist distinguished the ordinary 
trachee terminating in little ampulle and the trachee termi- 
nated by little tubes destitute of a spiral filament, which he 
named the capillaries of the trachee. M. Agassiz expresses 
himself as follows :—‘‘ In the grasshoppers which I injected 
by the dorsal vessel I found in the legs the muscles elegantly 
covered with dendritic tufts of these vessels (the capillaries of 
the trachez) all injected with coloured matter; and in a por- 
tion of a muscle of the leg of an Acridium flavovittatum, sub- 
mitted to a high magnifying-power, I observed the distribution 
of these little vessels, which has a striking resemblance to the 
* Translated from the ‘Comptes Rendus,’ July 27, 1868, tome Ixvii. 
pp. 242-244, 
+ Proc. American Association, 1849, pp. 140-143; translated in Ann. 
des Sci. Nat. 5° sér. xv. pp. 358-362. 
