A New Acarite. By M. A. L. Donnadieu, DSc. 283 
affected by the old and still vexed question, as to whether the 
nucleus exists distinctly or at all in the corpuscle while it circu- 
lates within the living blood-vessels, or is formed only after its 
exposure to the atmosphere or chemical reagents. Many years 
ago De Blainville, Valentin, Henle, and others, and more recently 
Savory, supported the latter view; and the former was adopted by 
Mayer and Kolliker, to which Brunke has lately conformed. The 
subject cannot be entertained here ; only it may be noted that I 
have satisfied myself of the substantial accuracy of Mr. Savory’s 
observations on the blood-disks of some British Batrachians, but 
not of the validity of his conclusions therefrom, and that I have 
plainly seen in certain fishes the projections on the corpuscles, 
indicative of a nucleus, while they were flowing within the living 
blood-vessels.” 
The facts, described above, were shown in the living fish at a 
late scientific meeting, at Canterbury, of the East Kent Natural 
History Society, and were regarded with much interest by the 
members present. 
IIL—A New Acarite. By M. A. L. Donnaninv, D.Sce., Professor 
at the Lyceum of Lyons. 
Puate CLXXXIILI. 
In the month of April, 1873, in emptying into a plate full of weak 
acetic acid * the contents of a collection from a sweeping net, I 
found an acarite which appeared to me to be quite new. It is diffi- 
cult for me to give any exact idea as to its origm. The glass was 
full of acarites of all kinds, Scirus, Trombidium, Gamasus, &e., and 
with them a great many insects, among which the Diptera were 
most numerous, more especially those allied to the common fly. 
With regard to the specimen which I found, which, in spite of 
EXPLANATION OF PLATE CLXXXIII. 
Fic. 1.—AHeterotrichus inequarmatus. Entire animal seen from behind. The 
left half is represented without the numerous hairs which cover the body, in order 
to show the tubercles which support these hairs. 
Fic. 2.—A tubercle very much enlarged, and showing the two kinds of hairs. 
a. Long and pointed hairs divided into segments. 6. Short hairs with the 
peculiar spherical swelling. 
Fic. 3.—Extremity of one of the feet. a. Tarsus. 6. Edge of the cupuliform 
membrane deprived of hooklets. c. Two large internal hooklets. d. Nine small 
spatuliform hooklets. jf. The three large external hooklets. g. hairs, 
Fic. 4.—Acarite magnified twice. 
* See, for an explanation of this process of research, ‘ Recherches sur les 
Tétramiques,’ par A. L, Donnadieu, 1875, p. 27. 
VOL. XVII. Y 
