FISHERY BULLETIN: VOL. 71, NO. 2 



The best stain was obtained with IV2 min in 

 Wright's followed by 20 min in Giemsa's 

 stain; that slide was used in this study. 



Cells were examined under oil immersion 

 at 800 and 1200 power. Cells were measured 

 at 800 power. Cell classification followed that 

 of Saunders (1966a) for elasmobranch blood 

 cells. 



RESULTS AND DISCUSSION 



This deepwater Portuguese shark had larger 

 blood cell sizes, a lower hematocrit, and a 

 different white cell differential count than 

 those reported for other sharks. 



Cell Differentials 



id/im^ 



Figure I. — Mitosis-Prophase. 



Six classifications of cells were present: 

 mature erythrocytes, immature erythrocytes, 

 lymphocytes, heterophils, neutrophils, and 

 thrombocytes. I found no monocytes, eosino- 

 phils, or basophils in the material I studied. 



Mitotic division occurs in the circulating 

 blood, for mitosis, in all stages, was present 

 in a few cells in the blood smear (Figures 1, 2). 



An erythrocyte differential count of a ran- 

 dom sample of 100 red cells revealed that 

 mature erythrocytes constituted 92% of the 

 total, immatures 7% , and erythroblasts 1% . 



The percentage of mature red cells agrees 

 closely with Saunders' (1966a, b) findings for 

 other elasmobranchs, but the white cell dif- 

 ferential of this shark differed substantially 

 from those of other elasmobranchs reported 

 by Saunders. This shark had 73% lymphocytes, 

 22% thrombocytes, and 5% heterophils; whereas 

 in 13 species of elasmobranchs Saunders found 

 a maximum of 32% lymphocytes and 20-85% 

 thrombocytes, and in 9 species, 3-54% hetero- 

 phils. The large difference in lymphocyte fre- 

 quency may be an individual characteristic of 

 this specimen, for Saunders found a substantial 

 difference between the white cell differentials 

 of two adult specimens of sandbar shark, 

 CarcharhhiHs milberti. Saunders also reported 

 that either heterophils or neutrophils, but not 

 both, are found in any given species of elasmo- 

 branch; however, I found a few neutrophils 

 in addition to heterophils on close examination 



Figure 2. — Mitosis-Anaphase. 



of the blood in this shark. Several were located 

 at the end of the smear where a differential 

 would not normally be made because of mechani- 

 cal distortion of the cells; others were dis- 

 covered in the area where a differential might 

 be made, though the neutrophils could be 

 easily overlooked because of their scarcity. 



Table 1 lists the measurements of all cells 

 described in this report. 



Mature Erythrocytes 



The mean size of the Portuguese shark 

 mature erythrocytes (Figure 3) is the largest 



436 



