MICR ousTEs.—The mammalian teeth from German and English trias indicate a very small insectivorous quad ruped, to which the above generic name was given by Professor Plieninger. The German specimens were discovered in 1847 in a bone breccia at Diegerloch, about two miles from Stutt gardt, the geological relations of which are well determined as between has and Beuper sandstone. The teeth of Micro/estes from Frome, submitted to the writer by the discoverer, Mr. Charles Moore, F.G.S., in 1858, are four in number, two being molars of the upper jaw, each with four fangs ; one a molar with a narrower crown and two fangs from the lower jaw ; and the fourth a small, pointed, front tooth. The crowns of the molars are short vertically in proportion to their breadth ; the distinct enamel contrasts with the cement-covered fangs ; the grinding surface shows a wide and shallow depression, sur rounded by small, low, obtuse cusps, three of equal size being on one side, a larger cusp near one end, and smaller and less regular cusps on the side opposite the three. One lower molar shows a similar type, but with the three marginal cusps less equal in size : a second smaller, and from a more anterior part of the series has three low cusps on one side, and but one cusp on the other side of the crown, the grinding surface of which presents an elongate triangular form. This tooth had two
fangs. The crown of the largest of the upper molars does not exceed one line in its longest diameter. Amongst existing Mammals, some of the small molars of the marsupial and insectivorous Myrinecobius of Australia offer the nearest resem blance to these fossil teeth ; but a still closer one is presented by the small tubercular molars of the extinct oolitic Mammal called Plagiaulax (fig. 93, m, and 2.).
DROMATHERIUM.—It would appear that the Mammal from the American triassic or liassic coal-bed (Dromatherium sylvestre, Emmons) also found its nearest living analogue in Myrinecobias ; for each ramus of the lower jaw contained 10 small molars in a continuous series, 1 canine, and 3 conical incisors, the latter being divided by short intervals.