PRODUCTID^. 331 



as stated above, I fear Prof. M'Coy has confounded two different species under his 

 desionation of L. tenuissime-striata. 



Genus — Cuonktes, Fischer. 



(See 'General Introduction,' p. 113.) 



No true species of Productus seems to have been hitherto discovered in the Silurian 

 rocks, altiiough several ill-understood and obscure specimens have been erroneously 

 referred to it. The genus CImietes, however, which forms part of the ^?a\i\\y Produdidce, 

 has been long known to occur in our Silurian strata. Although exteriorly Chonetes 

 often assumes the shapes of Leptana, it may be distinguished from it by its series of 

 sloping tubular spines on the cardinal edge of the ventral valve, as well as by the shape 

 of its muscular and reniform impressions. Only a very few species of the genus have 

 been found in Silurian strata ; it is much more abundant in those of the Devonian and 

 Carboniferous periods. 



Chonetes striatella, Dalman (sp.). PI. XLIX, tigs. 23 — 26. 



Pcctuiiculus planus flabelliformis, Bruckmann. Siles. Subterr., p. 338, pi. vii, fiw. 6, 



1720. 

 Pectiinciilite, TFalch. Das Steinreich, p. 151, pi. xiv, No. 3, fig. infer., 1769. 

 Calcareus testaceus, Brugman. Litliologia Groningana, p. 13. pi. i, fig. 1, 1/81. 

 Orthis striatella, Dalman. Kongl. Akad. Handl., p. Ill, pi. i, fig. 5 a, b, c, d, 1827. 

 Lept^na lata, Von Buck. Abhandl. Akad. Wissens. Berlin, pp. .53 and 70, pi. iii, 



figs. 1, 3, 5—9, 14, 15, 1828. 

 Orthis striatella, Kldden. Verstein. Mark-Brandenburg, p. 179, 1834. 

 Lept^na — Id. Ibid., p. 181. 



Orthis — Hisinger. Lethaea Suec., p. 70, pi. xx, fig. 7, 1837. 



Lept.^na lata, J. de C. Sow. Sil Syst., p. 160, pi. v, fig. 13 (non ibid., pi. iii, fio-g. 



10 6 and 12 c), 1839. 

 Productus sarcinulatus (partim). Von Buck. Abhandl. Akad. Wissens. Berlin, p. 25, 



(non ib., T. sarcinulatus, Schloth.), 1841. 

 Lept^na sarcinulata (partim), B^Archiac et De Verneuil. Geol. Trans. London 



ser. 2, vol. vi, part ii, p. 397, 1841. 

 Strophomena sericea (?), Emmons. Nat. Hist. New York ; Geolog}', part ii, p. 394, 



pi. 105, fig. 1, 1842. 



