SPERMATOGENESIS OF PASSALUS CORNUTUS. 409 



their study of the living cells of Chorthippus (Orthoptera) found 

 that mitochondria were present in the primary spermatogonia in 

 the form of granular threads; but there is no evidence for such 

 structures in Passalus. 



The secondary spermatogonia are arranged in cysts in the 

 form of a rosette, and are generally pyramidal in shape. Both 

 nuclear and cytoplasmic volume is noticeably smaller in these 

 than in the primary gonia. The cytoplasm always shows a 

 marked affinity for the hsematoxylin and this is due to the 

 presence of numerous mitochondrial granules (Figs. 4, 23) which 

 are scattered diffusely throughout the cytoplasm. Payne (1917) 

 found granular mitochondria in the spermatogonia of Gryllotalpa, 

 while Duesberg (1910) figures similar structures in Blaps. On 

 the contrary Duesberg describes the mitochondria of the gonia 

 of Blatta as being present in the form of threads (chondrioconts). 

 Payne, Schafer ('07) and others have found that the mitochondria 

 of the spermatogonia are localized at the inner ends of the cells 

 (i. e., the end bordering on the cyst cavity). As I have before 

 stated, in Passalus the mitochondria are diffusely spread and 

 often are actually absent from the inner ends of the cells. Mont- 

 gomery (1911) was unable to find evidence of "indubitable 

 mitochondria" in the spermatogonia of Euschistus, although he 

 found granules which he considered to be disintegrated idiozome 

 material. 



Fig. 5 shows a degenerating spermatogonium. It is noticed 

 that the cytoplasm is much more deeply staining and the mito- 

 chondrial granules are much larger. The chromatin of the 

 nucleus is concentrated into one or two karyosomes. The in- 

 crease in the size of the mitochondrial granules is probably due 

 to an agglutination of the smaller normal ones. Cowdry (1916) 

 in his excellent review on the functional significance of mito- 

 chondria, has called attention to the relations of mitochondria in 

 pathological tissues. He mentions the work of Scott who found 

 that in fatty degeneration of the pancreas there was an agglutina- 

 tion of the mitochondria. It is quite possible that the degen- 

 eration of cells which is so common in insect spermatogenesis is 

 of the fatty degeneration type. A study of the behavior of the 

 mitochondria in degenerating sperm cells may throw some light 



