252 M. Agassiz, Recherches sur les Poissons Fossiles. 



" If naturalists who carry on researches of this nature do not abuse these facilities, 

 they will become in future more and more easily attainable, and thence will result 

 real advantages to science. In my own case I have derived great advantage from 

 having been enabled, by the direct comparison of the fragments scattered through 

 many collections, to complete the character of many new species, and to prove the 

 existence of a great number of others, many of which must have remained doubtful 

 from the inspection only of very incomplete fragments. By this means I have been 

 able to select for my drawings those specimens only which give the most exact idea, 

 and to complete my descriptions from the whole. M. Dinkel, the artist by whom 

 the greater number of the original plates of my " Researches on Fossil Fishes" were 

 designed, is now in London, occupied in delineating all those specimens which have 

 appeared to me indispensable for the completion of my work. When he shall have 

 made some progress, I shall revisit London to compare his designs with their origi- 

 nals, before returning the latter to their owners." 



In his way homeward from Ireland, M. Agassiz, as our readers are aware, 

 visited Bristol ; following his report, let us enumerate what he found here. 

 His principal wish in visiting Bristol was to examine the fossils of the 

 carboniferous limestone, a formation little known on the Continent, but 

 from which he expected a good deal, judging from some specimens in M. 

 Cuvier's collection, and some fragments which he had met with elsewhere. 



" My expectations," he proceeds, " were not deceived. The museum of the Philoso- 

 phical Institution contains the beautiful collection of its first curator, that indefati- 

 gable naturalist, Miiller, and by consequence the originals whence were taken the 

 plates of his work on the crinoidea. By the assiduous care of Mr. Stutchbury the 

 present curator, and of Dr. Riley, the museum is daily increasing ; it is more par- 

 ticularly remarkable for its magnificent collection of the fossils of Bristol and the 

 neighbourhood. With respect to fishes, I found there many new species and even 

 genera, from the carboniferous limestone, though only their teeth and the spinal 

 rays of their dorsal fins ; they belong to the family of the cestraciontes. 



"I observed there also an immense number of fragments from a sort of osseous 

 brecchia (bone bed) found among the inferior beds of the lias ; among these fossils 

 are many new species, and many which appear to me to be identical with those 

 collected by Keuper and M. Alberti, in Wurtemburg. The other fishes of the lias 

 possess large palates, provided with many ranges of teeth, like the acrodus and 

 hybodus of Lyme Regis. There are also many hybodontes and pycnodontes, as well 

 as icthyodorulites, from the great oolite, ^^ and from Stonesfield]; and some teeth, 

 palates of the rays, and some heads from Shoppy. The institution is indebted to 

 Dr. Fox for a superb specimen of a new species of tetragonolepis, from the white 

 lias of Banwell, and to Messrs. M. Wright and W. Clayfield, for beautiful specimens 

 of icthyodorulites, from the lias and from the coal of Dudley. Mr. J. N. Sanders has 

 reposited in the institution a fossil ray, certainly among the most important of the 

 discoveries made in the lias of Lyme. Dr. Riley has very correctly described this 

 animal under the term squalo-raia, and has assigned it its true place among the 

 cartilaginous fishes. Mr. Grant, taking, after Dr. Riley's description, the prolonga- 

 tion of the snout for the jaws, has considered it rather to be a reptile ; but the 

 attentive examination that I have been permitted to make of it, has made me confi- 

 dent, that it is a particular genus of the ray family, different from any now existing. 

 It is unfortunate that the name squalo-raia indicates an exaggerated affinity to the 

 squall., it would perhaps be better to term it spina corhinus." 



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