new SuJtspcciei o/" Spalax inonticola. 315 



groove. Of the faint costre found frequently in turcicus by 

 Mehely 1 can see no trace in thermaicus. 



Cheeh-tCfth. — In adult stao;es of wear tlie patterns of the 

 cheek-teeth are exactly sinidar to those of turcicus. The 

 anterior sulcus separating the two tubercles of which the 

 front lobe of 1l} is oritrinally composed (cf. Mehely, Mamni. 

 p. 206, ^^. 9) is always ej)!ienieral in thermnicns^ tliough 

 sometimes f)ersistent in turcicus. In thermaicus the young 

 ^^ is quite like !!!ii, having three re-entrant enamel fohls on 

 the labial side instead of the single " zweibuchtigc " fo'd 

 found in turcicun; the posterior or third labial fold is very 

 small, it is quickly reduced to an islet, which, in turn, 

 speedily disapjtears: '±1 and ^JLJ have each to begin with 

 tliree lingual re-entrant folds (in addition to the labial fold): 

 but the posterior labial " fold " commences as an islet in the 

 posterior lobe of the tooth ; the two anterior labial folds have 

 u common moutii on the side of the tooth and are separated 

 from each other internally by a small saliency fornied by the 

 posterior horn of the half-moon-shaped anterior moiety of the 

 young tooth. In the ,^;n; of "ly youngest specimen this 

 saliency appears as a se[)arate tubercle not yet united wiiii 

 the main mass of the tooth. 



Molar I'oots and the alveoli. — The molar roots tend to be 

 reduced by fusion in thermaicus^ while they remain free and 

 distinct in turcicus. In the latter "iiJ, according to M^hdy, 

 is always distinctly three-rooted, having two labial roots and 

 a lingual root, which tends to be forked; correspondingly 

 the alveolus has tliree distinct cells, that for the linoual root 

 .showing two depressions. In tkeruuiicus the anterior labial 

 root is very short and it is completely fused with the lingual 

 root, being separated from the latter merely by a faint 

 crease ; a furrow also divides superlicially the large lingual 

 root into two parts ; the posterior labial root is completely 

 free, though short. The alveolus has a special cell with com- 

 })lete walls oidy for the posterior labial root ; its remainder 

 shows three depressions — a shallow one for the anterior root, 

 ami two deeper ones for the lingual root, in thermaicus Ulil 

 is similar to ^ as rigaids roots and the alveolus; but the 

 division of tlie lingual root only becomes perceptible towards 

 the tip, and in the alveolus the septum dividing the cell ibr 

 the posterior labial root from the remaintlur of the alveolus is 

 lower and tliinner. In turcicus this tooth has three distinct 

 roots, of which the lingual is always more or less distinctly 

 forked, while the alveolus is correspondingly four-celled. In 

 turcicus — ? also is |)rovidcd with three completely free roots, 



