05 8 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



tinct reptiles like Hypsilophodon, Lcdaps, and others the 

 ascending process of the astralagus shows itself as an avian 

 character. A few years ago Professor Wyman discovered 

 that this process had an independent centre of ossification, 

 and therefore could not be a process of the bone. Mr. Morse 

 had interpreted this bone as the " intermedium " of Gegen- 

 baur. The intermedium is a tarsal bone, occupying a position 

 between the astralagus and the calcaneum. In the saurians, 

 turtles, and other reptiles this bone is well seen. In certain 

 amphibians, as in the salamanders, the bone is long, wedge- 

 shaped, and partially projects between the tibia and fibula. 

 Mr. Morse has expressed his belief that the ascending process 

 of the astralagus represented the intermedium of reptiles. 

 He had published in the "Annals of the New York Lyceum 

 of Natural History " a theoretic figure of the proper position 

 of this bone in birds, comparing it with the intermedium of 

 certain salamanders. He explained its position in front of the 

 tibia as a supposed process of the astralagus, calling atten- 

 tion to the excessive tendency to anchylosis in birds. The 

 widening: of the tibia to include all the tarsals within its 

 width necessarily brings the intermedium in front of the 

 tibia, and, as it early unites with the astralagus, has natural- 

 ly been mistaken. Mr. Morse has been able to confirm his 

 opinion regarding the nature of this bone in studying the 

 embryos of common tern at the Anderson School of Natural 

 History, at Penikese Island. In the embryo bird the inter- 

 medium showed as a long oval bone, the astralagus and cal- 

 caneum passing up between the tibia and fibula, as seen in 

 the lower reptiles. 



In this connection it is interesting to observe that in the 

 mammalia the intermedium does not occur, and Gegenbaur 

 has expressed the opinion that the astralagus and interme- 

 dium united. These investigations might possibly go to 

 confirm that opinion by the fact that in reptiles the interme- 

 dium is separate; in birds it is separate in the young bird, 

 but connected witli the astralagus in the adult state ; while 

 in mammals, if Gegenbaur is right, it is always so connected. 



SEX IN THE EMBRYO. 



Mr. E. Van Beneden publishes in Gervais's Journal a paper 

 on the original distinction of the testicle and the ovary, in 



