334 SYNOPSIS OF THE VERTEBRATE FAUNA OF THE PUERCO SERIES. 



MiOCLiENUS ZITTELIANDS Sp. nOV. 



This species is represented by a skull which lacks the occipital region. It is 

 enclosed in a silico-calcareous concretion, and the teeth have been cleanly exposed by 

 weathering, but the surface of the skull is not cleaned. Large parts of both mandi- 

 bular rami with their teeth are preserved. 



The dental characters resemble those of the M. turgidus, but differ in the absence 

 of intei-nal cusps of the superior premolars. The dimensions are smaller, especially 

 those of the premolar teeth. The last molar in both jaws is much smaller than the 

 others, as in M. kmjidus, and tiie intermediate tubercles in the superior molars are 

 present, but small. The external cingulum is distinct on the superioi- true molars, 

 but wanting on the premolars. The same is true of the anterior and posterior cin- 

 gula, while internal cingula are absent from all the teeth. The heels are rudimental 

 on the first and second inferior premolars. 



Measurements. M. 



Length of superior molar series 036 



" " " true molars 014 



( anteroposterior 00o5 



Diameters superior p. m. i < „„„ 



( transverse UU i 



C anteroposterior 0U55 



Diameters superior ni. ii < „._„ 



I transverse 00,3 



Width between p. m. ii on palate 0075 



" " m. ii on palate 015 



From the Upper Puerco. Dedicated to Professor Karl Zitlel, of the University 

 of Munich, and Director of the Museum. 



MlOCL^NUS TUnniDDNCULUS sp. nov. 



This species is primarily indicated by a portion of a left maxillary bone which 

 supports the first two true molars, and the first premolar. There is a mandibular 

 ramus supporting the corresponding teeth of the inferior series, which probably be- 

 longs to the same species, and the posterior parts of two other rami, each supporting 

 the last two molars, are also referred to it. 



The peculiarity of the superior molars consists in the strong external cingulum 

 and intermediate tubercles, and the large size of the first premolar, and especially of 

 its internal cusp, in which respects it resembles that of the MloclcBnus ojnstJiacus. It 

 has no cingula whatever, except a trace at the anterior and posterior external angles. 

 There are anterior and posterior, but no internal cingula of the true molars. In the 

 M. minimus the molars have no cingula, except faint traces of the anterior and pos- 

 terior, and the intermediate tubercles are wanting. 



