

1910.] Tupaiidcp and Macroscelididce. 285 



as Indrodon and Olhodofcs. This ancestral Menotyi)hlan family also very 

 probably resembled the ancestral Lipotyphlan in the dental formula (l^io)' 

 well developed milk dentition and general characters of the skull and skele- 

 ton. The postorbital processes were slight, the brain case smaller, the 

 tympanic process of the petrosal (destined to expand into the entotym- 

 panic) might have been scarcely larger than it is in Solenodon. The arrange- 

 ment of the foramina also may have approximated to the primitive Lipo- 

 typhlous condition, /. c, with separate optic foramen, rotundum confluent 

 with for. lac. anterius, entocarotid entering tympanic chamber from the rear 

 and giving rise to three branches, "sinus canal" prominent; stapes widely 

 open. In the skeleton digits II, III, W were subequal, digit III being 

 slightlv the longest; a large centrale carpi, entepicondylar foramen, third 

 trochanter, and many other primitive mammalian characters which are 

 ascribed below to the more remote common ancestors of both Menotyphla 

 and Lipotyphla. 



The Tertiarij Historij of fJie Menotyphla. 



The Tertiary history of the Menotyphla is unknown, unless, indeed the 

 Middle Eocene (Bridger) Insectivore Eviomolestes grangeri (Matthew, 1909) 

 shall prove to be a member of the Tupaiidie. It was formerly thought that 

 Galerix Pomel, from the Miocene of Europe, was related to Macroscelides 

 but Leche has shown that it is a typical Gymnurine and therefore an Erina- 

 ceid (Weber, 1904, p. 382). A comparison of the skull of the Oligocene 

 Leptictid Icfops with those of Tupaia and the Macroscelididae does not lead 

 to any decisive results. Icfops seems much more primitive than the modern 

 forms in the basicranial region and in the dentition; but, as the fibula had 

 already become fused with the tibia and the astragalus seems to have had a 

 well grooved trochlea,^ this genus cannot be directly ancestral to the Tupai- 

 idfe, and it seems probable, from the greatness of the morphological gap 

 between the Tupaiida^ and the Lipotyphla, that the two suborders must have 

 diverged at a very early date, possibly much before the Lower Eocene. 



The relations of the Menotyphala with the Primates are discussed below 

 (pp. 321-322). 



1 (cf. Doufflass, 1906, pi. xxii.). 



