326 The Spermatozoa of AUolobophora Foetida 



Photo 2. Spermatozoon from the same spermatophore, though not the 

 same slide as Photo 1. The magnification is less, i. e., 660. The two gran- 

 ules in the middle-piece were not clearly differentiated in this preparation, 

 and we therefore focused on the apical granule. The apical granule is 

 more constantly differentiated than the granules in the middle-piece which 

 require a magnification of one thousand diameters for satisfactory illus- 

 tration. Photos 3, 4 and 5 further demonstrate this point. 



Photo 3. See under Photo 2. Mag. 660. 



Photos 4 and 5. Spermatozoa from two spermatophores collected five 

 days apart. Mag. 450. These preparations were photographed to show the 

 constancy of the presence of the apical granule. The lower magnification 

 was used to bring into the field a larger number of spermatozoa than is 

 possible with a 2 mm. lens. 



Photo 6. Anterior end of a spermatozoon from the same spermatophore 

 as the spermatozoon shown in Photo 1. On every slide dried in the air, 

 or by heat, there are areas in which entire spermatozoa, or definite parts 

 of them, are much fiattened, sometimes the chromatin of the head flowing 

 into a broad, thin layer, in some cases with a line of alveolar cytoplasm on 

 each side of the head, and sometimes the tail splitting into parallel fibres. 

 This is due perhaps to rapid and uneven drjdng. In such spermatozoa, the 

 three granules are much more clearly differentiated. We have selected a 

 few preparations to illustrate this. In Photo 6, the chromatin of the 

 anterior part of the head is flattened, as described above, and the apical 

 granule sharply differentiated. The effect on the form of the head, pro- 

 duced by the flattening, is seen by comparing the part of the head next 

 the spine, with the part cut by the edge of the photo. Mag. 1000. 



Photo 7. Anterior end of a spermatozoon, showing spine and part of 

 head. The head is much flattened and almost completely severed from the 

 apical granule, which is thus sharply differentiated. Mag. 1000. 



Photo 8. Spermatozoon showing spine, apical granule and head, the 

 middle-piece with" anterior and posterior granules and a part of the tail. 

 The part of the head next the middle-piece is slightly flattened and the tail 

 also is flattened and split into parallel fibres; this condition of the head 

 and tail allowing a sharp differentiation of the two granules in the middle- 

 , piece. Mag. 1000. 



Photo 9. Spermatozoon with flattened head, showing apical granule and 

 the two granules of the middle-piece. C. f. Photo 6. Mag. 1000. 



Photo 10. Spermatozoon, showing spine, apical granule, head with anter- 

 ior half slightly flattened, and part of the tail. Mag. 1000. 



Photo 11. Part of the head of a spermatozoon much flattened; middle- 

 piece showing anterior and posterior granules, and part of the tail split 

 into parallel flbres. Mag. 1000. 



The spine with apical granule was not included in this photo, because 

 not on the same plane with the middle-piece, and thus requiring a different 

 focus. 



Photo 12. This spermatozoon M^as photographed to show the fibrillar 

 structure of the tail, this splitting of the cytoplasm of the tail being due 



