On the Supposed Fish Remains figured on Plate 4 of the ‘Silurian System’
1853; Geological Society of London; Volume: 9; Issue: 1-2 Linguagem: Inglês
10.1144/gsl.jgs.1853.009.01-02.09
ISSN2058-105X
Autores Tópico(s)Paleontology and Evolutionary Biology
ResumoHaving pointed out to Sir Roderick Murchison, about two years ago, the great resemblance which the so-called Onchus Murchisoni (fig. 10 of the above plate) bore to the slender didactyle pincers of a Silurian Crustacean which I have figured in the first Fasciculus of the 'Cambridge Palæozoic Fossils' Pl. 1. E. fig. 7, under the name Pterygotus (Leptocheles) leptodactylus , it occurred to him that examination might prove some of the other remains described by Prof. Agassiz as fishes in the 'Silurian System' to belong to the same class, and he accordingly sent me all the specimens, now accessible, figured on that plate, to examine and report upon. The specimens sent to me only belonged to the Thelodus parvidens and Onchus tenuistriatus , together with a fragment called on the plate "an Ichthyodorulite" (figs. 63 & 64), but I venture a few observations on all. Figs. 1, 2, & 3, supposed to be shagreen of Sphagodus , I cannot determine without seeing the specimens. Figs. 4 & 5 ; although these scale-shaped markings are stated to belong to a fish called Pterygotus problematicus , still M. Agassiz, in his volume on the Fishes of the Old Red Sandstone, very properly removes this genus from the class of Fishes and places it in its true class, Crustacea . I have suggested, in the work on the Cambridge Fossils, that Pterygotus belonged, not to the Macrurous Crustacea, but to the group Pæcilopoda , allied to the recent Limulus or King-crab, and recent discoveries published in this Journal confirm
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