BLENNIOIDS. GADOIDS. 161 



and cockles, lobsters, sea-urchins, &c., should soon wear off these 

 small enamel points, which cannot therefore have much fanctional 

 importance. These transitory summits, which are composed in 

 reality of a fine tubular dentine, were supposed by Cuvier to be the 

 true teeth, and to be peculiar to the young wolf-fish : he gives a 

 figure of one of them in PI. 32, fig. 6, a, of the Lecons d'Anatomie 

 Coraparee, vol. v, 1805. 



The calcification of the dentinal pulp proceeds in nearly parallel 

 lines from the summit to the base of the tooth ; it is this peculiarity 

 in the wolf-fish that occasions the solidity of the teeth, and the 

 genera] straight course of the medullary tubes ; most of these run 

 parallel to each other and to the axis of the tooth ; but the tubes 

 nearest the sides of the tooth slightly diverge towards that sur- 

 face. Tracing the medullary canals from the basis of the tooth, they 

 divide dichotomously into finer and parallel branches, which form 

 numerous reticular anastomoses together and terminate in fine 

 loops at the periphery of the tooth. The medullary canals are 

 occupied by processes of a vascular pulp ; they were seen and 

 described by both Cuvier and Von Born, who conceived them to 

 be the channels of the nutrient vessels and nerves, and they were 

 rightly compared by the latter anatomist to the similarly conspicuous 

 tubes which traverse the teeth of the Orycterope ; but the structure 

 of both teeth is much more complicated than that of the horn of the 

 rhinoceros, or of the baleen of the whale. The minuter or calcigerous 

 tubes which traverse the firm substance occupying the interspaces of 

 the medullary canals were not perceived in either case, by the above- 

 cited anatomists ; they are extremely minute in the Anarrhichas, and 

 do not form by their parallel and straight course a distinct enamel- 

 like outer layer, as in the pike, except at the apex of the recently 

 formed teeth, but are confined to the fine and inextricable reticulate 

 anastomoses at the periphery of the tooth as well as in the inter- 

 spaces of the medullary canals. 



GADOIDS. 



62. The dental system maintains a greater uniformity in the 

 Cod -tribe than in most of the other natural families of the class of 



M 



