Ch XXII. ] 



FOSSIL MAMMIFER IN TRIAS. 



341 



Fig. 440. 



Fig. 441. 



Microlefites antiquus, Plieninger. Molar tooth ina2;ni- 

 fied. Upper Trias, Diegerloch, near Stuttgart, WUr- 

 temberg. 

 a. View of inner side ? h. Same, outer side? 



e Same iu profile. d. Ci'owu of same. 



Microlefites antiquus, 

 Plien. 



View of same molar 

 as No. 440. From a 

 drawing by Her- 

 mann Von Meyer. 

 a. View of inner 



side? 

 &. Crown of same. 



Molar of Microles- 

 tes? Plien. 4timea 

 as large as the fig. 

 440. From the 

 trias of Diegerloch, 

 Stuttgart. 



Professor Plieninger inferred in 1847, from the Fig. 442. 



double fangs of this tooth and their unequal size, and — 



from the form and number of the protuberances or 

 cusps on the flat crowns, that it was the molar of a 

 Mammifer ; and considering it as predaceous, prob- 

 ably insectivorous, he calls it Microlestes, from ixocpocr, 

 little, and Xyiftr-rig, a beast of prey. Soon afterwards, 

 he found the second tooth, also at the same locahty, 

 Diegerloch, about two miles to the southeast of Stutt- 

 gart. Some of its cusps are broken, but there seem 

 to have been six of them originally. From its agree- 

 ment in general characters, it is supposed by Professor 

 Pheninger to be referable to the same animal, but as it is four times as 

 big, it may perhaps have belonged to aijother allied species. This molar 

 is attached to the matrix consisting of sandstone, whereas the tooth, fig. 

 440, is isolated. Several fragments of bone, differing in structure from 

 that of the associated saurians and fish, and believed to be mammalian, 

 were imbedded near them in the same rock. 



Mr. Waterhouse of the British Museum, after studying the annexed 

 figs. 440, 441, 442, and the descriptions of Prof. Plieninger, observes, 

 that not only the double roots of the teeth, and their crowns presenting 

 several cusps, resemble those of Mammalia, but the cingulum also, or 

 ridge surrounding the base of that part of the body of the tooth which 

 was exposed or above the gum, is a character distinguishing them from 

 fish and reptiles. " The arrangement of the six cusps or tubercles in two 

 rows, in fig. 440, with a groove or depression between them, and the 

 oblong form of the tooth, lead him, he says, to regard it as a molar of the 

 lower jaw. Both the teeth differ from those of the Stonesfield Mammalia, 

 but do not supply sufficient data for determining to what order they be- 

 longed. 



Professor Plieninger has sent me a cast of the smaller tooth, which 

 exhibits well the characteristic mammalian test, the double fang ; but 

 Prof. Owen, to whom I have shown it, is not able to recognize its affinity 

 with any mammalian type, recent or extinct, known to him. 



It has already been stated that the stratum in which the above-men- 

 tioned fossils occur is intermediate between the lias and the uppermost 



