29S ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



plex horns result from the direction of the main axis or line 

 of greatest increase: in the wapiti, or American elk, as well 

 as in the stag of Europe, this is along the protoceres through- 

 out, while in the common Virginian and long-tailed deer it is 

 procurrent subspirally into the tritoceres. The Elaphure of 

 China is anomalous in the excessive development of the deu- 

 teroceres, or homologues of the brow-antlers of the wapiti and 

 sta<x, and the inverse reduction of the other elements. 



The Placenta of Prosimians. 



One of the most interesting groups of mammals is that of 

 the Prosimians, comprising the lemurs, the Tarsius, and the 

 aye-aye, most of which are found in the great island of Mad- 

 agascar. The special interest arises from the fact that, in 

 many points of structure, they approach the apes and man 

 more than does any other form. On account of the posses- 

 sion of their many common characters, the two groups of 

 Apes and Prosimians have been, by most writers, combined 

 under the ordinal designation of Primates, although quite a 

 number of prominent naturalists have urged that the two 

 should be differentiated as distinct orders. The question 

 was reopened several years ago by Mr. A. Milne-Edwards, 

 who examined the placentation of several species of Prosim- 

 ians, and found that it differed widely from that of the Apes. 

 The placentation of species of the group has still more thor- 

 oughly been investigated, during the past year, by Professor 

 W. Turner, of Edinburgh, who has in part confirmed and 

 amplified the observations of Mr. Milne-Edwards. His ex- 

 amination extended to three species viz., Lemur rirfipes, 

 Propithems diadema, and Indris brev icaudata. 



A number of prominent zoologists have combined the or- 

 ders of placental mammals under groups distinguished by 

 the placenta. In one type, as in Man, the uterus develops 

 a decidua, and the placenta is discoidal ; such are Man and 

 the Apes, the Bats, the Insectivores, and the Rodents. In 

 others the placenta is deciduate and zonary, as in the Car- 

 nivores and the Proboscideans; and in a third the uterus 

 develops no decidua whatever, as in the Ungulates and Ce- 

 taceans. Until the discovery of the placentation of the Le- 

 muroids, it had been very naturally assumed that they pos- 

 sessed a discoidal deciduous placenta like the apes. It is 



