Dr. Thomas Wright — Cotylederma in the M. Lias. 505 



IV. — On the Occurrence of the Genus Cottledebma in the 

 Middle Lias of Dorsetshire. 



By Thomas Weight, M.D., F.B.S.E., F.G.S. 



PKOFESSOK QUENSTEDT, in his Handbuch der Petrefakten- 

 kunde (1852), first described and figured, under the name 

 Cotylederma, a remarkable fossil which be found adherent to the sur- 

 face of Ammonites striatus in the upper region of the Lias c. It 

 formed a flat, sessile, cylindrical little bowl, composed of five plates, 

 with five blunt angles, and was referred by him to the class Echino- 

 dermata and the order Crinoidea. The learned author, in his " der 

 Jura" (1858), says that he has found it attached to Ammonites 

 lineatus and A. striatus in the upper region of Lias <y, at Aselfingen, 

 and that it was comparable to the calyx of a crinoid. 



Professor E. Deslongchamps, in his valuable memoir : " Sur la 

 Couche a Leptasna" (Memoires de la Societe Linneenne de Nor- 

 mandie), described and figured several forms of this genus, which 

 he had found in a very richly fossiliferous stratum of Middle Lias 

 at May and Fontaine Etoupefour (Calvados). The Cotylederma are 

 very singular Crinoids, of which we only know the Calyx or Pelvis. 

 They have the form of little cups or tubes, and adhere directly by 

 their base to submarine bodies without any trace of a stem. These 

 remarkable fossils are very abundant at May, and from this locality 

 Professor Deslongchamps obtained many specimens, among which 

 are several new species, as Cotylederma miliaris, Desl., Cot. fistulosa, 

 Desk, Cot. docens, Desl., Cot. vascidim, Desl., Cot. Quenstedti, Desl. 



M. Terquem collected a species of Cotylederma sessile on an 

 ammonite in the Middle Lias (Department of the Moselle), in a bed 

 with Ammonites Davcei, Sow., and which was identified as the Cotyle- 

 derma Quenstedti, Desl. 



MM. Terquem and Ed. Piette (Lias Inferieur de Test de la France, 

 p. 128) have subsequently detected this genus in the Lower Lias 

 Limestone with Ammonites bisulcatus, Brug., at Fleigneux and at 

 Jamoigne in the East of France, where they found six individuals of 

 different ages ; five were attached to Grypho&a arcuata, Lam., and 

 the sixth and largest specimen to Pleurotomaria anglica, Sow. These 

 they have described and figured as G. Oppeli. " The base is firmly 

 adherent, lobed into five or six divisions ; the superior border thin, 

 round ; interior conical smooth. Dimensions : Diameter of the base, 

 6 millim. ; diameter of the opening, 2 to 3 millim. : depth, 2 millhn. 

 The specimens are very rare." 



My friend F. Longe, Esq., F.Gr.S., whilst examining the Lias 

 Coast Section last August between Lyme Eegis and Charmouth, 

 found a nodule at the base of Down Cliffs which he thinks belongs 

 to bed d, " Blocks of indurated Sandstone," of Mr. Day's memoir on 

 the Middle and Upper Lias of the Dorsetshire Coast. (Quart. Journ. 

 Geol. Soc, 1863, vol. xix. p. 285, fig, 4.) This nodule contained a 

 specimen of Cotylederma, having a portion of shell adhering to its 

 base. The fossil is conical, obliquely inclined to one side ; the base 

 is expanded, and was apparently adherent ; and the summit is 



