434 Sir P. G. Egerton on some new genera and species 



A. semivei-rucosus, Egerton. This species rests upon a single 

 specimen in the Dorchester Museum. It is characterized by its 

 short and falciform figure, and by the peculiarity of the surface 

 ornament, consisting of an intermixture of coarse tubercles 

 with raised lines, similar to those on the spines of the genus 

 Hybodus. 



Locality, Purbeck beds, Swanage. Decade 8. pi. 3. 



A. papillosus, Egerton. Although not a British species, this 

 is alluded to as completing the enumeration of the species of this 

 genus. It is an ichthyodorulite of short and massive proportions, 

 having its surface invested with large round papillse. 



Locality. Oolite, Caen. 



Genus Pholidophorus, Agassiz. 



P. granulatuSy Egerton. This species more nearly resembles 

 the P. ornatus of Agassiz than any other. It differs in the deeper 

 proportions of the body and in the characters of the scales, which 

 are more oblong and have the striations finer and more regular, 

 and the posterior margins less deeply serrated. Those in the 

 vicinity of the dorsal fin are granulated. 



Locality. Purbeck beds, Swanage. Decade 8. pi. 4. 



Genus Histionotus, Egerton. 



This genus has some affinities to Lepidotus and Semionotus. 

 It resembles the former in the outline of the head and trunk, 

 and the latter in the large size of the dorsal fin. This organ 

 however occupies a much greater extent of surface, commencing 

 near the nape of the neck and reaching almost to the caudal fin. 



H. angularis, Egerton. The species is characterized by the 

 abrupt angles occurring at the occiput and at the insertion of the 

 dorsal fin. The scales somewhat resemble those of a large Pho- 

 lidophorus and are similarly articulated ; they are finely serrated 

 ^ on the posterior margin. The teeth are fine and conical. 

 Locality. Purbeck beds, Swanage. Decade 8. pi. 5. 



Genus Aspidorhynchus, Agassiz. 



A. fisheriy Egerton. This is a slender species, differing in its 

 proportions from any of the species figured in the ' Poissons 

 Fossiles.* The scales along the dorsal line are curiously figured 

 with irregular vermiform ridges running longitudinally. The 

 teeth are sharp and numerous. 



Locality. Purbeck beds, Swanage. Decade 8. pi. 6. 



