1893.] DB. C. J. FORSYTH MAJOR Oy MIOCEN-E SQriERELS. 185 



shape of inferior molars tends to disappear. The species which 

 present in a greater or lesser degree this conformation are, besides 

 Xervs (Plates YIII. and IX. fig. 10), including A', r/etttlvs, Gesn. 

 (Plates YIII. and IX. fig. 9), >Sc. palUatus, Pet., Sc. cejiajn. Smith 

 (Plate YIII. fig. 22, Plate IX. fig. 23), Sc. j^'P-rojws, Y. Ciiv. 

 (Plate YIII. figs. 15, 23, Plate IX. figs. 15, 22), Sc. con,/la(s, Kuhl, 

 Sc. lenmiscatvs, Le Conte, *SV. isahella, Gr. (Plates YIII. and IX. 

 fig. 24), and Sc. hoehmi, Eeieh. At the same time they present in 

 their skull some resemblance to the Ilystricomorplia. They also 

 approach Anomahtms (Plates YIII. and IX. figs. 13, 14), the 

 various hystricomorphine characters of which have long ago been 

 noted, but have, I think, rather been nndei-rated by Alston \ 



It thus would appear that ^^•e ha^ e here a group of Sciuromorpha, 

 somewhat specialized in the direction of Hystricomorpha, as we 

 find, too, in several Eocene Rodentia. 



But this is not all. The molars of Sc. herdmorei, Bly. (Plates 

 YIII. and IX. figs. lG-18), an Oriental Squirrel, and those of the 

 Boniean " lihinosci^mis, Gr.'' (Plates YIII. and IX. figs. 11, 12), 

 agree with those of Xems and the above-named Ethiopian Squirrels, 

 not only in their semi-hypsodontism, but likewise in their lopho- 

 dontism, whilst the less scmi-hypsodont Oriental Sc. tristriatus, 

 AYaterh., and Sc.jxdmcirnm, L., tend to connect the .Y€/-?(S-type with 

 the Sc-vvlijans-ix^e, in approaching the form of molar of most 

 of the " middle-sized " Oriental Squirrels. Two other Oriental 

 species, »SV. insi;/nis, F. Cuv. (Plates YIII. and IX. fig. 6), and 

 Sc. hosei, Thos.'-^ (Plates YIII. and IX. fig. 5), from Borneo, 

 though semi-bypsodont, and in other characters agreeing with 

 the members of the A'c/'H.9-group, show a remarkable modification 

 in the pattern of the molars, the valleys being reduced to mere 

 superficial cracks, which disappear very early by wear. I think 

 that we have in the molars of these two forms examples of that 

 kind of reti'ogressive evolution of the molars to «-hich attention 

 has been lately drawn in an important paper by Leche ^, who 

 attributes it to the modification of food. The Macroijlossi, Ptero/His 

 scapulatus, and the EiiomojJiori, differing in this respect from 

 other Pterojti, feed on juicy fruits, whose contents need not be 

 chewed. Likewise Chironu/s madaf/ascarieims, the molars of 

 wliich present a similar kind of retrogi-essive evolution, is lalo^^■n 

 to feed principally on succulent juices, especially of the sugar- 

 cane, as well as on wood-boriug caterpillars. It now is very 

 suggestive that Sciurvs in.si;/ms, according to Miiller and Schlegel ', 

 is especially fond of juicy and aromatic fruits of different species 



1 Edward R. Alston, "On Aiioma/urug, its structure and position" (Proc. 

 Zool. Soe. 1875, p. 94). 



■' Ann. Mag. Nat. Hist, for Sept. 1892, pp. 21.5, 216. 



^ W. Leche, " Stiidien dber die Entwieklung des Zahnsysteius bei den 

 Saugethieren," Moi-pholog. Jahrbuch, xix. 1892, pp. .54.3, 544. 



* Sal. Miiller & Hei-ni. Selilegel, " Over de tot heden bekeude Eekhorens 

 (^Sciurus) van den Indisehen Archipel," Yerhandeliugen over de Naturlijke 

 Greschiedenis der Nederlandsehe overzeesche Bezittingen," Leiden, 1839-44, 

 p. 99. 



