380 ORTMANN — DISTRIBUTION OF DECAPODS [Aprils, 



have existed. Already Meddlicott and Blanford (1879, p. lx) 

 have doubted that the plain of the Ganges river was covered by 

 the Cretaceous ocean, and, although these authors generally disbe- 

 lieve the existence of such a strait during Jurassic, Cretaceous and 

 Tertiary times, Diener (/. c, 1895) has demonstrated that there 

 exists, in the central Himalaya mountains, an almost complete 

 series of sediments from the Cambrian to the Eocene, among 

 which Triassic and Jurassic beds are well represented, while Creta- 

 ceous beds apparently are missing and Eocene again is known. 

 This is very much in favor of a connection of India with Asia 

 during the Cretaceous. A very positive opinion on this question 

 is expressed by Kossmat (1895, p. 463). He says that the Middle 

 and Upper Cretaceous ocean of southern and eastern India was 

 not connected over northern India with Europe. 



Therefore, it seems to be well to assume only for the Jurassic 

 period and for the Lower Cretaceous a separation of India and the 

 Sinic continent ; that is to say, during these times Lemuria (Mada- 

 gascar-India) was a peninsula connected with Africa. In the Mid- 

 dle and Upper Cretaceous, this peninsula became united with the 

 Sinic continent, forming a land-bridge between the latter and 

 Africa. This connection, however, was apparently interrupted 

 again in Eocene times. According to Neumayr (/. c, p. 481), 

 the Eocene deposits of the Central Mediterranean Sea (Nummulite- 

 beds) are continued across the whole of northern India to the 

 Gulf of Bengal (and farther to Java, Borneo and the Philippine 

 Islands), and indicate thus a continuous ocean, which isolated 

 India from the rest of Asia. Since, at about the same time 

 (Eocene), the destruction of the Lemurian bridge took place, 

 India became an island, as is first pointed out by Koken. In Post- 

 Eocene times, this strait separating India and Asia disappeared, 

 and we have, in northern India generally, at about this time (cer- 

 tainly from the Miocene upward), a regression of the ocean (see 

 Meddlicott and Blanford, 1879, p. liii). The island of India was 

 definitively joined to Asia and never again separated. 



After the destruction of the connection of India with Madagas- 

 car, in the beginning of the Tertiary, of the southwestern parts of 

 Lemuria only Madagascar remained, which was still connected, as 

 a peninsula, with East Africa. Then this connection was also 

 severed, but not before the Oligocene or the beginning of the Mio- 

 cene. Thus the main outlines of the present distribution of land 



