282 Bulletin American Museum of Natural History, [^'ol. XX^'II, 



the mastoid, squamosal and exoccipital is also swollen and cancellous, 

 recalling similar conditions in the Rodent family Heteromyidtne and in 

 Phascologale among Marsupials. The brain case is large and rounded but 

 narrow between the orbits (contrast Twpaia). The orbital fossa is very 

 large but the postorbital processes are absent (Macroscelides) or small {Petro- 

 dromus). The malar extends back to the glenoid, as in Tupaia certain 

 Rodents and Marsupials. The malar has a large anterior surface for the 

 insertion of the anterior part of the masseter (c/. Tupaia). The glenoid 

 fossa is extended anteroposteriorly more than in Tupaia and much as in 

 primitive Rodents. The palatal vacuities are very extensive antero-poste- 

 riorly. This "Marsupial" feature is reinforced by the prominent raised 

 posterior rim of the palate and by the palatal foramen at the postero-external 

 angle of the palate. (A similar foramen appears in Ictops and other Lipo- 

 typhla and in certain Creodonts.) A large interparietal is figured by Parker 

 in Rhynchocyon {op. cit., pi. 36), and this genus appears to agree further with 

 lipotyphlous Insectivores in having a median perforation in the basisphenoid 

 (probably for the vestigial notochord) and cartilaginous pterygoids. The 

 vomer is stated by Parker {op. cit., p. 275) to have the postero-lateral wings 

 "as large as in average Marsupials" {cf, Solenodon, p. 253). 



Ossicula auditus. According to Doran (1879, pp. 440-442, 444, pi. 62, 

 figs. 15, 16) the malleus in the Macroscelididae is of very peculiar type. In 

 the Lipotyphla the processus gracilis (Folii) is curved so as to fit accurately 

 to the tympanic ring, as in Marsupials, but in Macroscelides and Rhyn- 

 chocyon the processus gracilis forms a thin straight bar which fits into the 

 Glaserian fissure; the extremely constricted neck and the narrow lamina 

 are also characteristic. The malleus of Petrodromvs departs less widely 

 from the Sorex type. The incus of Petrodromus tends toward that of Tupaia. 

 The stapes in the Macroscelididse has straight crura as in Tupaia (contrast 

 the curved crura of Lipotyphla); the stapes is perforated by a bony canal 

 for the stapedial artery, as in Lipotyphla. 



Cranial foramina, etc As described by Mivart (1867, p. 296) the optic 

 foramen is large and very slightly separated from the sphenoidal fissure. 

 In Rhynchocyon Parker (1885-86, p. 275) found that the optic was entirely 

 confluent with the foramen lacervmi anterius. A suboptic foramen, analo- 

 gous to that in the Erinaceoidea and Centetidea is also present. The 

 foramen rotundum, as in most Insectivores, is confluent with the foramen 

 lacerum anterius. The alisphenoid canal is absent (contrast Tupaiidee) 

 and there is also no supraorbital foramen. The lachrymal foramen "opens 

 well wdthin the orbit" (contrast Tupaiidfe). Mivart also states that there 

 is a "small carotid foramen near the margin of the auditory bulla (imme- 

 diately opposite the middle of the occipital condyle)." The mental foramen 

 "opens beneath the antepenultimate molar" {cf. Tupaiid?e). 



