FISHERY BULLETIN: VOL. 71, NO. 2 



joKm^m 



t- 



10 Microns ^ 



Figure 4. — Heterophil showing rod-shaped granules. 



Figure 6. — Two thrombocytes, one with a fingerlike 

 cytoplasmic projection. 



Neutrophils 





t- 



lOMicrons 



H 



Figure 5. — Lymphocyte and three erythrocytes. This 

 lymphocyte does not have blebs extending from the 

 cell wall. 



Thrombocytes 



Thrombocytes, which are characteristically 

 some of the smallest cells found in the peripheral 

 circulation, were as large in this shark as 

 many mature erythrocytes in other vertebrate 

 species. The stained nucleus is ovoid with pink 

 to red dotted cytoplasm. Since there is quite 

 a range in the length of some of these cells 

 due to fingerlike cytoplasmic projections, I 

 measured 20 ovoid thrombocytes (Figure 6). 



Neutrophils were scarce and were discovered 

 only when the whole slide was studied in 

 detail. They are within the same size range 

 as the heterophils but are distinguished by the 

 absence of eosinophilic rod-shaped granules 

 and the colorless cytoplasm (Figures 7, 8). 



Figure 7. — Center: A neutrophil located at the end of 

 the smear where other cells have been mechanically 

 distorted. Clockwise: Immature erythrocyte, lymphocyte, 

 mature erythrocyte, and thrombocyte. 



438 



