SPLANCIINOLOGY, — The soft parts afford no material for such interesting observations as those of the monkey-s of the Old World. The larynx wants in general the pouches, which I have described before. There are but two exceptions yet known, one in the Ilia rikina (Hapcde rosalia), in which CUVIER and CARUS state that they have found a laryngeal pouch, which, according to CUVIER, communi cates with the larynx between the thyroid and cricoid cartilages. The second exception is the Ateles paniscus, in which there is a mem. branous expansion behind the cricoid carti lage. The hyoid bone of Ateles has the form proper to the monkeys of the Old World. In Cebus it approaches more to the form of man, by a more truncated pyramidal and a less convex or scutiform base.
The disposition of the laryngeal apparatus in the genus Mycetes deserves a more accu rate notice. It is distinguished, .as may be seen in .fig. 134, by a peculiar tympaniform dilatation of the base of the hyoid bone, by which a repercussion of the exhaled air seems to be produced. A great resonance, effected by the elasticity of the parietes of this bony cavity, must be the result of this repercus sion, by which the terrible howlings of these animals are produced.
Upon the other soft parts of the Cebince there is nothing very particular to say. I mention only the structure of the stomach in Ateles and Illycetes, in which, according to the ob servations of CUVIER and of Prince MAXIMI LIAN, there is some tendency to the saccu lated form of the stomach in the Semnopitheci. This peculiarity confirms all that I have said before about the analogy between Ateles and Semnopithecus. In the organs of generation the length of the clitoris is worth notice, particularly in Ateles and Cebus. According to the observations of LEucicamr * it has an os clitoridis, which grows larger at its anterior extremity. RUDOLPHI seems to have been misled by it, in his description of a presumed hermaphroditical monkey. It is very probable that he did not examine an hermaphrodite, but a fetnale Cebus capucinus.*
About the embyro-genesis of the Cebince RUDOLPH I published some interesting notices. He observed in the Ouistitis that the ompha loid vesicle persists till the last period of gestation, and that there are in Hapale, cetes, and Cebus two umbilical veins, which unite near the liver.
As an appendix to all these anatomical observations about the Cebince, I join the re sults of the dissection of Nochthora trivirgata, which I made in the month of July, 1843, in the Zoological -Society of London. The sto mach has the transversely oblong form proper to the monkeys in general, and not the round form of the Stenops ; consequently the ccecal sac is not so ample as in Stenop8. The ccecum terminates in a more elongated ccecal point than in Stomps. It wants cells, as in the greater part of the American monkeys. In the encephalon the hemispheres are larger in their anterior lobes ; they cover almost the whole cerebellum ; the fossa SYLVII is trans verse, and very deep ; the mesial lobes are very distinct ; the asymetry between the two hemispheres is not so distinct as in Stenops, by all which characters the brain of the Noch thora trivirgata approaches to the monkeys, and differs from Stenops. The laryngeal ap paratus has a great deal of analogy with that of man; the thyroid cartilage is large and prominent, and has almost the same form as in man. The epiglottis is much developed, particularly at its base. The arytenoid, car tilages are much elevated. The rznza glottidis is wide. The tongue differs from the same organ in Stenops, in which it is sustained by a triangular and flat cartilage. In the Nock !kora, on the contrary, it has the general structure of the tongue of the monkeys, being long and narrow, with isolated papilla.. The heart has an oblong form. The first ramifications of the arezts aortce are similar to those of man. The right lung is divided into four, the left into two lobes.