416 ON THE ANATOMY OF THE CRESTED AGOUTI. [J une 26, 



plantar surface of the joints, between the metatarsal bones and the 

 digits. 



Summary of Facts. 



Before concluding our observations on the Crested Agouti, we 

 must express our regret that circumstances occurred which caused 

 us to forego a description of the brain, part of the nervous and the 

 vascular systems, and the muscles of the back and neck. 



Of the facts here recorded we may recall, as more or less note- 

 worthy, the unconstricted condition of the stomach of D. cristata, 

 the much greater length of its large intestine as compared with 

 that of D. aguti, the tendency towards a double apex of the heart, 

 the approximation of the ureters to the fundus of the bladder, and 

 the presence of a superficial long femoral artery. 



As regards the comparison instituted between the Crested Agouti, 

 the Guinea-pig, Hare, and Rabbit, we find that the first differs from 

 all the others, and stands alone, in the following particulars : — 1, the 

 number and arrangement of the pads of the pes and manus ; 2, the 

 great extension of the levator claviculfe ; 3, the absence of the rhom- 

 boideus capitis ; 4, the more extensive insertion into the humerus of 

 the third part of the pectoralis major ; 5, the absence of the pecto- 

 ralis minor ; fi, the more distinct separation of the coraco-brachialis 

 into two, and its extension further down the shaft of the humerus ; 

 7, the insertion of the brachialis anticus below the biceps ; 8, the 

 presence of a flexor brevis manus ; 9, the less marked division of the 

 semimembranosus ; ] 0, the absence of the peroneus brevis. 



On the other hand, the Agouti agrees with the Guinea-pig, and 

 differs from the Hare and Rabbit (as far as our observations go) in 

 the subjoined conditions: — 1, the presence of the pads beneath the 

 pes and manus ; 2, the two fleshy bellies to the digastric ; 3, the 

 peculiar scalenus anticus ; 4, the single posterior scalenus ; 5, the 

 more distinct division of the psoas magnus ; 6, the less intimate 

 union of the psoas and iliacus ; 7, the large size of the supinator 

 brevis ; 8, the remarkable palmar ossicle ; 9, the fact that no tendon 

 of the deep flexor goes to the pollex ; 10, the great size of the glu- 

 teus medius ; 1 1, the gluteus minimus being smaller than the gluteus 

 medius; 12, the less strong and distinct tendon of insertion of the 

 biceps femoris ; 13, the larger rectus femoris; 14, the smaller and 

 less fleshy adductor magnus; 15, the double head of the tibialis an- 

 ticus; 16, the presence of an extensor hallucis ; 17, the absence of 

 a tibialis secundi ; 18, the presence of an extensor brevis digitorum 

 pedis ; 19, the absence of a peroneus quinti digiti ; 20, the presence 

 of sesamoids at the origin of the gastrocnemius; 21, the union of 

 the tendon of the last with the soleus ; 22, the separate conditions 

 of the bellies of the flexor longus digitorum and flexor longus hallu- 

 cis ; 23, the presence of a tibialis posticus. 



How far these myological distinctions may extend, whether any 

 are due to mere individual variation, or whether some may serve 

 to characterize the respective genera or even families, more extended 

 observations can alone determine. It is difficult, however, not to 



