264 Bulletin American Museum of Natural History. [Vol. XX^'II, 



Solrnodon in the chisel-like enlargement of the anterior incisors and in certain 

 featnres of the skull (p. 242). But a comparison of the base, and top views 

 of the cranium of Mi/ogale with that of the Talpidae (Dobson, 1883, pi. xx) 

 leaves little doubt as to the Talpoid affinities of this grouj). This impression 

 is confirmed by the characters of the scapula (Dobson, /. c, pi. xv) and 

 humerus, in which, however, the Talpoid peculiarities are still in an im- 

 emphasized condition. 



The dental characters of the Myogalina^ are clearly represented in the 

 Miocene Talpoid Proscalops ISIatthew (1905.2, 1909, pi. li; cf. Fig. 17, no. 9, 

 above). 



The tympanic region in Myogale is of especial interest because it eluci- 

 dates the structure of this region in the Talpoidea and furnishes a strong bond 

 of affinity between the Soricoid. the Erinaceoid and the Centetoid super- 

 families (vide infra). The tympanic wing of the basisphenoid is greatly 

 expanded and forms with the In'oad ring-shaped tympanic a large com- 

 posite bulla which on the anterointernal end extends to the mesopterygoid 

 fossa and almost meets its fellow of the op|iosite side. Anteriorly the tym- 

 panic ring is partly embraced by the well developed tympanic branch of the 

 alisphenoid; posteriorly the petrosal also contributes a tympanic branch to 

 the bulla (cf. SoJenodon, p. 246) and van Kam})en suggests (1905, p. 452) 

 that this branch is homologous with the entotympanic of ]Menoty])hla and 

 Marsupials. The large entocarotid foramen deeply notches this branch 

 of the petrosal. The Eustachian foramen is seen near the anterior end of 

 the bulla, at the junction of the tympanic wings of the ali- and basisphenoids 

 with the true tympanic annulus. Immediately external to the foramen 

 ovale is a foramen, which seems comparable with the foramen for the inferior 

 branch of the stapedial artery in Erinaceus (p. 247). 



The affinities of the Soricoidea are discussed below (p. 265). " 



Genetic Interrelations of tpie Lipotyphlous Insectivores (Summary). 



The preceding observations afford strong evidence for the inference that 

 the Lipotyphlous Insectivores form a natural group divisible into the four 

 well separated superfamilies which were recognized by Gill in 1872, viz: 

 the Centetoidea (including the Centetidse Potamogalidse and Solenodontida?), 

 the Chrysochloroidea (including the Necrolestidee and Chrysochloridse), 

 the Erinaceoidea (including the Leptictidaj ErinaceidjB, Dimylidje) and the 

 Soricoidea (including the Soricidt^, Myogalidje and Talpidfe). The Chryso- 

 chloroidea are probably a specialized offshoot of the Centetoidea and the 

 two superfamilies form a natural group, the Zalambdodonta of Gill (1885), 

 which, however, scarcely ranks as a suborder, unless the I^ipotyphla as a 



