220 RODENTIA. 



its small end runs a little way down in that membrane. The spleen is 

 not very long, has three edges, and lies in the left side of the posterior 

 portion of the epiploon, as in most animals. 



In one from Mr. Banks there was a small detached spleen about 

 3 inches from the large or common one. It lay in the doubling of the 

 epiploon 1 . 



The heart is short and broad, not peaked at the point as in the sheep. 

 The auricles are very much like one another, rounded on their anterior 

 edges. There is but one vena cava superior. The lungs are as in 

 most other animals, the left divided into two lobes, the right into 

 four. The kidneys are conglobate, very pro min ent^ nearly of an equal 

 height ; the right rather the highest. 



On examining the external parts of generation, we found two swell- 

 ings on each side of the anus like testes, but they are glands that 

 throw in a thick mucus into the verge of the anus, as in the guinea- 

 pig, but are larger ; which anus in this animal is a pretty large opening, 

 externally, as it were, common to these two glands and the rectum. 

 These parts are hardly covered with hair. The opening of the prepu- 

 tium is very near the anus, just under the bulb of the urethra, from 

 which opening the penis passes forwards towards the belly, for about 

 one half of its length, and then is bent back again to the pubis, and 

 along the symphysis of this bone, so that it lies doubled : this is like 

 the guinea-pig and Virginia squirrel ; and, when erected, it becomes 

 straight 'and is wholly directed forwards. 



There is a bone in the centre of this retrograde part, and a small 

 bone on each side of that part that is covered by the preputium, like 

 two splints ; exactly the same as in the guinea-pig. The two testes are 

 very large, and He commonly within the abdomen, but the lower end, 

 which is the epididymis, just points through the rings of the abdominal 

 muscles, and appears a little prominent on the rings or inguen. The 

 tunica vaginalis can easily be inverted, and when so, the epididymis 

 seems to be attached to the lower part of the belly by a ligament, 

 similar to that which is found in the human foetus, and which has 

 the cremaster muscle lost on it. From this a ligamentous substance 

 goes across the penis on the bend, and would seem to draw these bodies 

 a little out of the abdomen when the penis is erected or made straight. 



There are two pretty thick small muscles that arise from the pubis 

 near the symphysis, between the body of the penis and symphysis, that 

 are lost in two tendons which run upon the upper or convex surface of 

 the penis, and by their action will extend that bent part as the extensors 



1 [Hunt. Prep. No. 839.] 



