76 Zoological Society — 



3 lbs. 1^ oz. By way of comparison I have taken a hare weighhig 

 7 lbs. and a rabbit weighing 3 lbs. .5 oz. I have measured and 

 weighed every part of importance, but I need only mention some of 

 the comparisons: — Brain of hare 210 grains, eye 75 grains, lungs 

 684 grains, heart (bloodless) 6.5.5 grains, trachea very large, length 

 of alimentary canal 18 feet. Brain of rabbit 125 grains, eye 35 grains, 

 lungs 1 93 grains, heart (bloodless) 1 1 9 grains, trachea very small, 

 alimentary canal 15 feet 1 inch. I may remark here that I have 

 sometimes found the intestinal tube in the hare (probably in young 

 specimens) much shorter than that before mentioned. I have com- 

 pared the spermatozoa, the blood-corpuscles, and the various viscera 

 not mentioned above, and I find no important difference in them. 



As regards the skeleton, I have been unable to discover any ap- 

 preciable difference, except in its size and in the length of the hind 

 extremities ; but in the Museum of the College of Surgeons there is 

 a skeleton of the Lop-eared Rabbit (Preparation 1949) ; and if the 

 posterior limbs are compared with those of the hare (Prep. 1914), 

 the resemblance will be found to be very great. 



In taking a retrospect of the anatomy of these animals we find a 

 great similarity ; the interesting and important differences are in the 

 heart, lungs, and trachea. These I pointed out in 1854, in a paper 

 read before the London Physiological Society, " On the Weight, 

 Form, Size of the Cavities, and Thickness of the Parietes of the Heart 

 in the Vertebrate Animals* ." On referring to the weights of the 

 above-named organs, it will be seen that the proportions are very re- 

 markable. Thus, the heart of the hare (and I speak from the exami- 

 nation of many specimens) is nearly five times the weight of that of 

 the rabbit ; the lungs are nearly four times as heavy ; and the calibre 

 of the trachea three or four times as great ; the rings of the air- 

 tube are about the same number in both. 



But it must be remembered that these are differences in degree, 

 and not in kind, and may be explained to some extent by the habits 

 of the animal. The comparative swiftness and durability of speed of 

 the hare require a larger and stronger circulating organ ; and the 

 same remark will apply to the respiratory apparatus. If, however, 

 we have this similarity of structure, in many respects (as is well 

 known) the habits of the animals are widely different. The period 

 of gestation in the hare is said to be a month, that of the wild rabbit 

 three weeks ; but I am not acquainted with any reliable evidence 

 upon this subject. The young of the rabbit are naked and blind ; 

 whilst those of the hare see, and have a hairy covering at birth ; the 

 number of young in the hare is from two to four, that of the rabbit 

 from four to seven (early in the spring I have generally found four). 

 The rabbit burrows, takes down from its body, covers its young and 

 leaves them at night ; whilst the hare (English) seldom, unless hard 

 pressed, will go to earth. Without pointing out minor differences, 

 1 have said enough to lead some to suppose that my first impression 

 was correct, viz. that the cross between the hare and the rabbit was 

 a more extraordinary one than that between the ducks in question. 

 * Lancet, 1854. 



