44 REPORT ON ZOOLOGY, MDCCCXLII I. 



" above amber brown, beneath dark cinereous, claw on thumb triangular., 

 hind foot very long." Body 3'2", tail 1'3". 



CASTORINA. Mention should not here, I think, be 

 omitted of the interesting account by Dierbach of the know- 

 ledge possessed by the ancients respecting Castor. (Isis, 

 1843, p. 373.) 



Lereboullet has obtained several specimens of Myopotamus 

 Coijpus in spirits, Avhich he had an opportunity of dissecting 

 (Instit. 1843, p. 372), and to Avhicli Ackermann had also 

 added some remarks upon the external characters and habits. 

 (Comptes rendus, xvii, p. 1236.) 



Lereboullet found the nipples in only one female, although he examined 

 four for that purpose. The female in question was pregnant, and contained 

 five young ones; its nipples were 12-14 millim. (5-6"') long. These 

 nipples were connected with mammary glands, placed immediately under 

 the cutaneous muscle, and composed of long, narrow, and delicate bands, 

 the structure of which coidd be readily made out with a simple lens. 

 The intestinal canal was sixteen times as long as the body ; the ca'cuni 

 extraordinarily developed. The liver consisted of a principal lobe divided 

 into three portions, a right lobe, a right lobule, and a left lobe without 

 lobule. 



ACULEATA. From Hystrix subspinosus, Licht., Gray has 

 formed a separate genus, Chtetomys, (Ann. Nat. Hist, 

 xiii, p. 69.) 



For this he relies upon the cranium and dentition, of which he has also 

 given a figure in the 'Voyage of the Sulphur' (p. 30, pi. 18, figs. 1-6). 

 Cranium broad, convex (without frontal protuberance), zygomatic arches 

 expanded, maxillae contracted. Each upper molar presents two principal 

 plicated plates of enamel, and a small one between them. The under molars 

 arc longish ; the first exhibits two circular rings of enamel, each of which 

 has one internal fold, and the posterior ring, besides this, presents a small 

 fold on the outer side anteriorly. Each of the other under molars has two 

 indented folds on the inner side, and one on the middle of the external 

 border. Pictet has given a much more accurate description of this animal 

 (Rev. Zool. 1813, p. 225), and he has also erected it into a distinct genus, 

 I'liY/i-iirlivci-tix, which he himself, however, soon (1. c. p. 319) recognized as 

 identical wilh (iray's Cluetomi/ti. As a specific name Pictet had proposed 

 that of PL Moricandi ; this species is, however, identical with Ch. 

 subspinosus. 



