836 DR. A. Gt?NTHFR ON AN AFRICAN SNAKE. [Nov. 19, 



belonging to a different order: — 1. Salmo salar; 2. Caranx tra- 

 chums; 3. Platessa flems ; 4. Syngnathus typhle. They are all 

 drawn to a scale of which each division is equivalent to joVu^ °f 

 an English inch, like all my other engravings of similar ohjects. 



Tt was made known by Hewson that there is no relation between 

 the size of the species and the size of its red blood-corpuscles in 

 members of different orders of Mammalia ; and my measurements 

 show that these corpuscles are as large in the tiny Harvest-Mouse 

 and Mole as in the big Horse and Giraffe. But about a quarter of a 

 century ago those measurements (Appendix to Gerber's 'Anatomy, 

 pp. 4 and 26, and Notes xcvni. and cxvm.* to Hewson's Works) 

 proved that there is such a relation throughout the class of Birds, 

 and in single orders or families of Mammalia ; that is to say, in the 

 class of Birds and in orders or families of Mammalia the smallest 

 blood-disks occur in the small species, and the largest blood-disks in 

 the large species of that class and those orders or families. In fine, 

 throughout the class of Birds there is as much uniformity in the 

 red blood-corpuscles as in some single orders of Mammalia, Reptiles, 

 and Fishes ; the short diameter of those constantly oval corpuscles 

 of Birds has a general agreement with the diameter of the circular 

 corpuscles of Mammalia ; and the relation, as above explained in the 

 highest two classes of vertebrates, has not yet been found in the 

 lowest two classes, though the smaller size of the red blood-corpuscles 

 in the little Smelt than in the larger species of the Salmonidse is 

 remarkable. And, as shown in ray old Tables of Measurements, 

 some exceptions there are to one or other of the foregoing rules, but 

 those rules generally remain unaffected by subsequent researches. 

 Indeed the relations of size of the red corpuscles of the blood in the 

 different classes of vertebrates, especially as regards respiration and 

 animal heat, are not without significance ; and this will become 

 more obvious and interesting as soon as our knowledge is extended 

 of the gradations of size and quantity of those corpuscles in relation to 

 the organization and economy of the species, concerning which some 

 important points have been discussed in the first volume of the "Lecons 

 sur la Physiologie et l'Anatomie Comparee," by Milne-Edwards. 



For an opportunity of examining the blood of living specimens of 

 Salmo fontinalis and Salmo ferox I have had the advantage, through 

 the courtesy of Mr. Frank Buckland, of the thriving fish in his in- 

 teresting museum of economic pisciculture at South Kensington. 



5. Note on the Black Snake of Robben Island, South Africaf. 

 By Dr. Albert Gunther, F.R.S., F.Z.S. 



[Received October 7, 1872.] 

 The majority of herpetological collections possess, among the 



t [This Snake was presented to the Society the 24th of September last, by 

 Mr. G. H. Bramwell Fisk. Robben Island lies in Table Bay, about 7 miles off 

 Cape Town.— P. L. S.] 



