1910.] Cnuiial Foramiiid in SdIchixIoii pararloxu.s. 247 



Inscctivores, is not distinct but is confluent with the foramen lac(M-uni 

 anterius. The foramen ovale (X^) is hirge and circular as in Centetes. It 

 ])erforates the ahsphenoid at a point just internal to the glenoid fossa of the 

 s(}uamosal. The internal and if on/ meatus (VIII), facial canal (VII), 

 foramen, lacernm posterius (IX, X, XI) and the condylar foramen (XII), 

 as well as the sphenopalatine (V,) post palatine canal (Vj) and the stylo- 

 mastoid (VII) foramina are all located about as in Centetes- The eondt/lar 

 foramen (XII) in one of the adults is double, as is not seldom the case in 

 Marsupials, Insectivores and Rodents (cf. p. 329). 



Foramina for the carotids. The alisphcnoid canal (Fig. 18, A"^, can, as.) 

 for the ectocarotid, artery is located as in Centetes and Ictops. As remarked 

 above (p. 246) an internal branch of this artery may have pierced the base 

 of the cranium internally to the foramen ovale. The entocarotid probably 

 entered the tympanic cavity in or near the deep circular notch between the 

 petrosal and the mastoid (Fig. 18, A^, for. st. vi.). In Erinaceus according 

 to Winge and other authorities (quoted by van Kampen, 1905, pp. 383, 429- 

 430), the entocarotid after entering the tympanic chamber from the rear 

 divides into two main branches : ( 1 ) an internal branch, the true entocarotid, 

 which perforates the basisphenoid at the anterointernal corner of the tym- 

 panic chamber, immediately back of th-e alisphenoid; (2) an external branch, 

 the stapedial artery, which pierces the stapes. This again subdivides into 

 two branches: (a) ramus inferior (arteria maxillaris interna), running for- 

 ward in a groove in the roof of the tympanic chamber, leaving the latter 

 through a notch in the tympanic wing of the alisphenoid; (b) ramus superior 

 (arteria meningea media), entering the cranial cavity through the foramen 

 spinosum, "gelegen vorn im Tegmen tympani in der lateral Wand der 

 Facialisrinne" (van Kampen, 190.5, p. 430). In the sectioned skull of 

 Solenodon the difference from Erinaceus in this region is so considerable that 

 I cannot positively identify the course of any branch of the entocarotid. 

 An oblique canal which tunnels the basisphenoid, entering near the antero- 

 internal angle of the petrosal and in the mid line joining its fellow of the 

 opposite side, at first sight suggests the true entocarotid canal of Erinaceus 

 and Centetes; but the fact that it does not open into the cranial cavity but 

 continues across the basisphenoid, suggests rather the venous transverse 

 canal, which is similarly located in Marsupials and Rodents. In the young 

 skull the large open foramen lacerum meditim recalls the somewhat similar 

 aperture in Ictops, and suggests that the true entocarotid may have entered 

 through this apertiu'e, as it does in typical Placentals. But in one of the 

 adidt skulls the roof of the tymj^anum is jn'eserved and seems to cover this 

 aperture completely. In Centetes the foramen lacerum medium is obliterated 

 by the hypertrophy of the tympanic wings of the ali- and basisphenoids. 



