from the NelyJibourhood of Edinburgh. 261 



tooth, so as to preseut an appearance almost as if a little extin- 

 guisher had been stuck on to the ])oint. Below tliis, which is 

 quite smooth, the polished surface is ornamt'iitcd with fine striie, 

 more marked in some specimens than in others, and which con- 

 sist, in fact, of very delicate linear depressions, often inteiTupted 

 and wavy. These are best marked just below the enamel cap, 

 and become lost towards the base of the tooth, which is dull 

 and smooth. Microscopically the teeth display a structure 

 quite similar to that described by Agassiz in Pygopterus^ and 

 by Messrs. Hancock and Atthey in Pahnoniscus Egartoni. 

 The pulp- cavity is simple and wide at the base, becoming 

 attenuated upwards into the body of the tooth ; the dentine 

 displays the same arrangement of radiating tubules, and is 

 crowned above by a cap of structureless " enamel," which also 

 sends down a very thin and delicate layer over the whole ex- 

 ternal sui-face. 1 formerly described the teeth as quite smooth ; 

 and so they seemed to be in the specimen then at my disposal. 

 The apj)arent absence of the striae in these Wardie specimens, 

 however, is evidently due to flaking-off of the external enamel 

 film above mentioned, the surface being at the same time left 

 rather dull ; and I have since seen specimens from that locality 

 in which the external polished surface still remains, and 

 which show the very same strife as those seen in specimens 

 from other localities, preserved in a softer matrix. 



The maxillary bone, represented in PI. XVI. fig. 7, is from 

 Shawfair, and, though undoubtedly belonging to the same 

 species, is proportionally shorter and broader than is usually 

 the case. I have another from Loanhead, which shows the 

 same peculiarity. Neither of these belonged to full-grown fish, 

 in which the maxillary often attains a length of 2| inches by 

 1 inch in breadth posteriorly. The teeth are of different sizes ; 

 the larger ones, measuring in ordinary specimens from 3- to | 

 inch in length, are an-anged in a row at somewhat iiTCgular 

 intervals ; and occupying a more external position on the edge 

 of the jaw is a line of smaller teeth, whose length varies from 

 about tV to g inch. Certain specimens from Shawfair and 

 Woolmet appear to have undergone much ])ressure, the bones 

 and scales being very thin, though retaining their markings as 

 distinctly as ever, and the teeth being considerably flattened, 

 especially at their bases, as might have been expected. In 

 these instances, however, the enamel cap remains unaffected, 

 standing out all the more distinctly, while the sti-ije on the 

 body of the tooth are also more strongly mai-ked. These 

 appearances are, I think, certainly due to changes occurring 

 during fossilization, and not to specific difference. 



