TRANSACTIONS OF THE SECTIONS. 135 



before lie eovdd obtain his degrees. T received his notes and wrote after them the 

 Monograph, which was edited in ltid by the Royal Academy of Sciences of the 

 Netherlands in its seventh volume (Ortleedkundig Ondersock van der Potto van 

 Bosnian door F. A. W. van Campen, Med. Cand. Uit zesse nagelasen aau 

 seekeningen byeen gebragt door J. van der iloeven (Met due Platen Amsterdam, 

 4to, 77 pp.). Except the female organs of generation, a species, scarcely known 

 thirty years ago, is now more completely investigated than many species of the 

 mammalia living in Europe. 



The little but very natural group of Mammalia called Lemuridce, is one with 

 whose investigation I have been often and at different times engaged. It is well 

 known that zoologists have given the name of a hand to every extremity in which the 

 thumb is opposable to the other fingers. Some have such only on the posterior ex- 

 tremities, as the opossum (Didelphis) of America and the Chironiya of Madagascar. 

 Those are called Pedimctna, or hind-handed. Others have this structure both in the 

 anterior and posterior extremities, as in the case in the greatest number of monkeys, 

 and in the lemurs (Quadrumana). Man is the only species of the order Bimana 

 where the opposable thumb exists on the anterior extremities only. Amongst the 

 Quadrumana the Lemuridae are distinguished by the nail of the second finger of the 

 hind feet, which is erected, compressed and sharp (of a subulate shape), while the 

 other fingers have flat nails. I found that in all the species the fourth finger, both 

 of the anterior and posterior feet, is the longest. In the apes, on the contrary, as in 

 most other mammals having five fingers, the third is the longest of all. To those 

 characters, sufficient perhaps for the systematic zoologist, we may add, after what 

 is known by the investigations of Cuvier, Fischer, Meckel, W. Vrolik, Burmeister, 

 A. Smith, Kingnia and myself, several anatomical characters, as, for instance, that 

 the lower jaw is divided into two distinct lateral parts (as in many other mammals, 

 but never in the monkeys) ; that the orbit is not closed by the interposition of the ala 

 magna ossissjrfwnoideihetween the malar and frontal bones, so that thefissura orbitalis 

 inferior is not distinct from the temporal fossa*; that there exists a flat, mem- 

 branaceous or aponeurotic tongue-shaped appendage beneath the tongue, terminated 

 in slender slips forming a pectinated tip ; that the first pair of cerebral nerves is 

 represented by large corpora mammillaria, and that the uterus (in those of which 

 the anatomy is known) has two eornua, and not that pyriform shape which it 

 assumes in the monkeys and in woman. 



The whole group is confined to the eastern hemisphere of our planet. The 

 greatest number of species lives only in Madagascar; some are found on the continent 

 of Africa in tropical regions; and some in East India, chiefly in the isles at the 

 south and east coast of Asia. 



I distinguish the Lemurina into two groups. In the first there is only one nail of 

 the hinder feet erected and subulate; in the other, not only the second, but also the 

 third has that shape. To this second group belongs only the genus Tardus, living 

 in Celebes, Borneo, and the Philippine Isles. It seems not to be proved that there 

 is more than one species of that genus. The tarsus is very elongated. 



To the first group belong all the other Lemurina. In those the superior inci- 

 sors are placed by two pairs, and a vacant space is left between them in the middle f. 

 Some of those have the tarsal bones elongated like Tarsius ; the calcaneum and 

 navicular bone forming two slender elongated bones placed near each other like 

 the radius and ulna in our fore-arm. This genus is Otolionus or Galago. In others 

 the tarsus is not elongated. Some have only two incisors in the lower jaw 

 (LicJianotus, Propithecus) ; others have four in both jaws. To this last subdivi- 

 sion belong the genus Lemur (stricto sensu) and Stenops. The first has a long tail, 

 the second a short, or only rudimental tail, or no tail at all. The last is the case 

 in the slender and small Ceylonese species (Stenops gracilis). All species oyStenops 

 have a short index to the fore-hand ; in Stenops Potto there is an exaggeration of this 

 generic peculiarity, and the index has only two phalanges. The species is further 

 distinguished by the peculiarity that some spinous processes of the neck, covered 



* In Tarsius the orbit appears lo be closed behind, but the deviation from the other 

 Lemuridce is more apparent than real ; the great ala of the sphenoid bone is not concerned in 

 the formation of the hind wall of the orbit, but the malar bone is enlarged. 



t Propithecus seems to make an exception, but it is more an apparent than a real one. Sec 

 Proceedings of the Zoological Society, 1832,p. 21. 



