90 M. O. Strobelt on the Anatomy and 



This is an organ inserted into the upper part of the wall of 

 the stomach, on the ventral surface, and surrounded by a 

 special enveloping membrane, which was observed by the last- 

 mentioned naturalist* in Phthirius inguinalis and Pediculus 

 vestimenti (23, p. 7, and 24, p. 38). Notwithstanding all my 

 endeavours, I have not succeeded in detecting an analogue of 

 this in our animal ; so that I think I am justified in supposing 

 that this stomachal disk is wanting in Hcematopinus tenui- 



rostris. 



Adipose Body. 



The adipose body of Hcematopinus tenuirostris consists of 

 a very great number of separate cells. These are of an 

 elongate oval form, often somewhat pointed at one end, by 

 which means they acquire apyriform appearance. A fine and 

 delicate membrane envelopes the yellowish green, finely 

 granular contents, which readily allow two nuclei to be 

 recognized. At one end of the oval cell, sometimes the 

 pointed, sometimes the obtuse one, is attached an exceedingly 

 fine pedicle, which connects the fatty body with the great 

 tracheal stems. Thus, especially between the tracheae and the 

 integument of the body, there is interposed a considerable 

 number of fat-cells. The length of an individual cell is on 

 the average 0*110 millim. ; their average breadth is 0*057 

 millim. Besides these there are, especially in the abdomen 

 small globular cells which attain only half the size of 

 those first mentioned. These also present a clear enve- 

 lope, finely granular, but darker-coloured contents, and a 

 pedicle. In the arrangement of the cells of the adipose body 

 there appears to be no regularity ; they lie sometimes singly, 

 sometimes united into a mass, sometimes in the neighbour- 

 hood of the stomachal wall, sometimes close to the integument 

 of the body. As regards the function of this body, Malpighi, 

 and, following him, especially Leydig, regard it as the " ana- 

 logue of the omentum of the higher animals." I would 

 rather, however, accept the opinion of Landois, who expresses 

 himself decidedly opposed to the above view, " as the adipose 

 body fundamentally considered will not bear comparison in 

 any single particular with the omentum " (23, p. 10). 



Dorsal Vessel. 



For a long time I tried in vain to get a sight of the dorsal 

 vessel of Hcematopinus tenuirostris. By the dissection of fresh 

 animals I could not succeed in preparing it. The extremely 

 simple method recommended by Landois, of placing the living 

 animal without any preparation under the microscope, could 



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