Teeth in the Centctidie. 539 



contrary to what i.s stated by Leclie *, younger spcciinen.s 

 of /. 1 and y. 2 always possess a well-developed posterior 

 basal cusp. 



In the case of Oryzoryctes, Microf/(tfe, and IjimnO(jah P. 1 

 may at once be di^tinguUhcil from P.d. I by the tact tiuit it 

 resembles J/. 1 much less than the latter does, which is 

 especially evident in the condition of the external cusps; the 

 foremost of these lies, in the case of P.d. 1 and the two 

 anterior molars, in the same longitudinal row as those 

 following it; in the premolar it is set higher up and is 

 separated by a greater gap from those behind. As already 

 mentioned, this difference is much less distinct in the case of 

 CenteteHj Ericulus^ and Echiaops. 



The number of the external cusps on fresh cheek-teeth of 

 the molar series is from four to five in Microgale, on P.d. 1 

 usually five ; in Oryzoryctes five on P.d. 1, as on M. 1 and 

 M. 2. These external cusps arc divided by a median gap 

 into an anterior and a posterior series ; where five cusps are 

 jiresent, there are in some cases two cusps in the anterior and 

 three in the posterior division — in others the reverse. la 

 P. 1 only three external cusps are found ; in the case of 

 Microgale the median one, in comparison with that on either 

 side of it, has become disproportionately large and lofty. 

 With reference to the various species oi Microgale the follow- 

 ing remarks must be nuide. M. Dohsoni: P.Y corresponds 

 in its carnassial-like condition pretty closely with the P. 2 of 

 Ericuhis, and similarly P. 2 of M. Dobsoni is almost iden- 

 tical with the P. 3 of Ericulus ; at the most, in the case of 

 the former, the internal cus]) is somewhat more strongly 

 developed; nevertheless in the latter also the tootli, as 

 already mentioned, has but two roots. P. 3 is a secodont 

 tooth with two roots ; this applies to all species of Microgale. 

 — In M. Coivani P. 2 differs but little from P. 1; in height 

 especially the two teeth are about equal, while in M JJohsoni 

 P. 2 is much lower than P. 1. P. 2 is only slightly more 

 compressed, and in consequence somewiiat more elongate ; 

 the " protocone " is developed to precisely the same extent 

 as on P. 1. A much greater amount of compression is 

 shown by P. 2 in the case of M. Thomasi, in which also the 

 " protocone " is unusually reduced in comparison with that 

 of P. 1. In the genus Microgale the maximum of com- 

 pression (parallel to the longitudinal axis) is found in the 

 case of M. gracilis ; nevertheless a feebly developed " proto- 

 cone " is still present on P. 2, while in the case of the tooth 



* Zoc. cit. p. 519. 



36* 



