38 



A Further Comparison of the Sizes of the Red 

 Cells of Some Australian Vertebrates. 



By J. BuETON Cleland, M.D., Cli.M. (Sydney). 

 [Read April 8, 1915.] 



To The Emu (vol. xi., 1912, id. 188) Dr. T. Harvey 

 Johnston and myself contributed a paper giving the measure- 

 ments of the red cells of a number of Australian vertebrates 

 that had been examined by us. 



During the visit of the British Association for the 

 Advancement of Science to Sydney in August, 1914, I contri- 

 buted a further paper, giving a summary of the results of 

 these measurements, and of others conducted since the first 

 paper was published. These further results, which ar& 

 included in the present paper, support the contention made in 

 the first conjoint paper, that the sizes of the red corpuscles 

 vary considerably, not only in the classes of vertebrates, but 

 amongst the orders, and even in some cases amongst genera, 

 and that a comparison of the sizes one with another may be^ 

 of some service in showing the relative relationships of families, 

 and sometimes even of genera, to each other. 



The measurements have all been taken from blood-slides 

 stained by the Giemsa dry method, wet fixation and staining 

 methods being impracticable in the fi€ld. Experience seems 

 to show clearly that the measurements thus obtained in good 

 films are reliable. 



The red cells of the mammals call for no special comment. 



Amongst the Aves, the emu has the largest red cells that 

 we have so far met with, ranging from 14 to 16'5 /ut- by 8*5 ta 

 9'5 /x. Then follow the Proce1l((?'ii formes, ArdeiforrueSy 

 F el ecani formes, and the Anseriforraes. These have measure- 

 ments approximating to 14 by 8'5 jm. Coracii formes have 

 apparently slightly smaller cells, followed by the hawks and 

 parrots. In the pigeons and cuckoos the size approximates 

 more to 12 to 13 fx by 7 to 8 /a. The highest order of birds, the 

 Passer/formes, have red cells ranging from 10 to 12 jui. It 

 may be noted that in the families Dicruridac and Cnrvidne 

 the size is a little greater than in the other families of this 

 order. 



Amongst the reptiles, the size is usually from 15 to 20 jm by 

 9 to 12 ^x, occasionally in some skinks as small as 14 or even 

 12 jii in length. The frogs show red cells usually of from 

 17 to 20 ih in length. Amongst the fish, the I)i]}7wi, aa 



