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Show 416 ON THE ANATOMY OF THE CRESTED AGOUTI. [June 26, plantar surface of the joints, between the metatarsal bones and 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 noteworthy, 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 claviculae ; 3, the absence of the rhomboideus capitis; 4, the more extensive insertion into the humerus of the third part of the pectoralis major; 5, the absence of the pectoralis minor; 6, 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; 10, 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 gluteus medius ; II, 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 anticus; 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 hallucis ; 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 |
