580 MR. R. B. SHARPE ON CERTAIN ACCIP1TRES. [Nov. 3, 



all my then measurements of the red corpuscles in this order those 

 of Phoca proved the largest ; and now this size is exceeded in Otaria 

 and Trichechus. The smallest red blood-corpuscles in the Carnivora 

 occur in some species of Viverra, Paradoxurus, and Heipestes. But 

 between several sections of this order there are curious irregularities 

 in the differences of the size of these corpuscles, which, as our know- 

 ledge extends, will probably prove of physiological significance : 

 meanwhile I have already shown that they have taxonomic value ; for 

 example, by the comparative magnitude of the red blood- corpuscles 

 alone the Canidse may be easily distinguished from Viverridse. 



Trichechus rosmarus. — This animal (the Morse orWalrus of popular 

 books) has the red blood- corpuscles still larger than those of the 

 Eared Seal. Some years ago a young Walrus arrived in a sickly 

 state, and died soon afterwards, at the Society's menagerie, when I 

 examined its blood and found it very rich in red blood-corpuscles, and 

 consequently of high specific gravity. Referring to my notes, it 

 appears that the mean of numerous measurements of the diameter 

 of the corpuscles was yyVy °^ an i ncn > being exactly the same as the 

 average diameter of the corresponding corpuscles of the two great 

 Edentates already mentioned. And this conclusion is confirmed by 

 recent measurements of the old specimens of the blood-corpuscles of 

 Trichechus ; they were so long since dried, and yet are still beautifully 

 perfect. Thus of all apyrenaematous red corpuscles, those of Elephas, 

 Myrmecophaga, Orycteropus, and Trichechus are the largest at pre- 

 sent known. 



The red blood-corpuscles of man are among the largest of the 

 Mammalia. No British animal of this class has them so large ; in 

 all my former observations red corpuscles distinctly larger than of 

 man were found only in six Mammalia, to wit, Myrmecophaga jubata, 

 Orycteropus capensis, Bradypus didactylus, Elephas indicus, E. 

 africanus, and Balcena loops. To these must now be added Tri- 

 chechus rosmarus and Otaria jubata. 



Structure and Form. — The red blood-corpuscles of the Hippopo- 

 tamus, Otaria, and Trichechus conform in structure and shape to the 

 regular apyrenaematous type. Nor among the Mammalia has any 

 indubitable exception to the apyrenaematous character of these cor- 

 puscles yet been found. 



4. Contributions to a History of the Accipitres or Birds of 

 Prey. By R. Bowdler Sharpe, F.L.S., F.Z.S., &c, of 

 the Zoological Department, British Museum. — I. On 

 the Females of the Common and South-African Kestrels. 



[Eeceived August 5, 1874.] 



(Plate LXVIII.) 



A short time ago I received from my friend Mr. Bygrave Wharton 

 a pair of Common Kestrels which he had recently obtained in Hert- 



