GERM CELLS OF ARGAS 655 



that they disintegrate before reaching a stage in chemical com- 

 position which corresponds to that attained by the true mito- 

 chondria at the time they form the ring. The association of 

 fat globules with the vesicular bodies at the time of their disinte- 

 gration also suggests an identity with typical mitochondria, if 

 the results and conclusions of Dubreuil ('11, '13) are accepted, 

 for he derives fat droplets very directly from mitochondria, and 

 a similar relation is suggested by Faure-Fremiet ('10) and others 

 for certain types of mitochondria. On the other hand, the work 

 of the Lewises ('15) throws doubt upon such a relationship, 

 although the possible influence of mitochondria in fat formation 

 is not denied. 



Finally the possibility should be considered that the vesicular 

 bodies may represent intra-cellular parasites. It is claimed by 

 Hindle ('11) that the organism (Spirochaeta gallinarum) which 

 produces spirochaetosis in fowls, passes through a stage in its 

 life history in which the spirochaete breaks up to form many 

 small, rounded bodies which he speaks of as 'coccoid bodies.' 

 These bodies are found in various tissues of the tick but more 

 particularly in the cells of the Malpighian tubules and in the 

 ovary. Marchoux and Couvy ('13) deny that this relationship 

 exists between the so-called 'coccoid bodies' and the spirochaete 

 and they claim that these bodies are normally present in the 

 tissue cells of species of ticks which do not carry protozoan organ- 

 isms. They are unable to decide upon the nature of these 

 structures, although, among other possibilities, they suggest a 

 relationship to mitochondria. A thorough study of cells from 

 the Malpighian tubules, salivary glands, crop and intestine of 

 Argas leads me to the conclusion that none of the cytoplasmic 

 inclusions found in the cells of these organs is to be identified 

 as at all similar in structure or behavior to the vesicular bodies 

 of the germ cells. In the spermatocytes and spermatids of other 

 species of ticks which I have examined (Dermacentor variabilis, 

 Ornithodoros turricata, Rhipicephalus sanguineus) are found 

 inclusions entirely homologous with the vesicular bodies of Argas. 

 The manner in which the vesicles appear at a particular stage 

 in the history of the germ cells, and the way in which they pass 



