986 



CLASS PISCES. 



to this family, but which has been referred to the Teleostean 

 Siluroids. 



Family Lepidotid^e (Sphlerodontid.e). — In the Lepidotida the 

 body is more or less fusiform, the upper scaled portion of the tail is 

 longer than the lower, and the fulcra of the fins are well developed. 

 The palatine, vomer, maxilla, and dentary carry rows of knob-like 

 teeth (fig. 926), while the premaxilla is furnished with teeth of a 

 chisel-like form. The type genus Lepidotus (fig. 926), with which 

 Spharodus is in great part identical, has a wide distribution both in 

 time and space. Thus, in Europe it ranges from the Muschelkalk, 

 or Middle Trias (where its scales have been described under the 

 names of Dactylolepis and Thollodus) to the Chalk, and it also 

 occurs in the Kota group of India, and the Cretaceous of Brazil 

 and of North America. The large button-like teeth of L. maximus 

 are abundant in the Kimeridge Clay, and specimens have been 



Fig. 926.— Lepidotus maximus ; from the Kimeridgian of Bavaria. Reduced. Larger 

 views of teeth and a scale are given in the corners. 



found comprising nearly the whole palate, and exhibiting the curious 

 manner in which the replacing teeth gradually turn over as they 

 come into use. The names JVephrotus, Cenerodus, Omphcelodus, 

 Hemilopus, and Asterodon, have been applied to molariform and 

 chisel-like teeth belonging to members of this family from the Trias 

 of Silesia and Thuringia ; while teeth of the latter type from the 

 bone-bed of the same period, in both Wiirtemberg and England, 

 described under the name of Sargodon, should, perhaps, be likewise 

 placed here ; and Neorhombolepis, of the English Chalk, appears to be 

 an allied form. 



Family Eugnathid^e (Saurodontid/e). — The body in this 

 family is long and slender ; the snout short ; the fins have fulcra, 

 the caudal being of a partially or completely masked heterocercal 

 type ; the vertebral centra may be either imperfectly or fully ossified, 

 and the teeth are pointed. The range in time of this family extends 

 from the Upper Trias to the Neocomian of Europe, but may, per- 

 haps, also include the Chalk. In the typical group we have Eu- 



