CRITICAL BIBLIOGRAPHY. 21 



many of their names are synonyms, it being highly probable that many of these 

 species are only varietal forms, or young. It is to be remarked that no mention 

 is made by de Ryckholt of de Koninck's or any other person's previous work on 

 the subject, save only one single specimen after Goldfuss. 



1849. In 1849 Capt. T. Brown issued his ' Fossil Conchology,' in which he 

 re-figured all those shells previously described and figured in the ' Ann. and Mag. 

 Nat. Hist.' (op. supra cit.) he also gave copies of the figures of those Coal-measure 

 forms figured and described by J. De Carle Sowerby {op. supra cit.), also of one 

 form figured by Rhind, and those from the ' Mineral Conchology,' and in addition 

 he described and figured Uuio Uttoralis and JJ. discrepans from Low Moor, Bradford ; 



Avicula mcdioliformis, Water of Leith (Naiadites). 



Modiola Williamsoni, Wakefield (Anthracomya), pi. lxxi, figs. 24, 25. 



subtruncata, Wakefield (Naiadites), pi. lxxii, figs. 15, 16. 



curtata, Wakefield (Anthracomya), pi. lxxii, figs. 19, 20. 



Robertsoni, Newcastle-on-Tyne (Anthracomya), pi. lxxii, figs. 24, 25. 



Moorei, Vale of Todmorden (Anthracomya), pi. lxxii, fig. 27. 



minuta, Low Moor (?), pi. lxxii, fig. 29. 



He drops the name Pachyodon, and returns to the old name TJnio. 



1851. J. W. Binney ('Manchester Lit. Phil. Soc. Trans.,' vol. x, p. 181, pi. i, 

 figs. 1, 2; pi. ii, fig. 1) published a paper on some trails and holes found in 

 Carboniferous strata which he thought might be due to molluscs, probably 

 Modiolx, from the shape of their casts. 



1852. F. A. Quenstedt, referring in his ' Petrefactenkunde ' to Coal-measure 

 Unios, describes a " glatter Leiste unter der Ligament." (He figures Anodonta 

 lettica, Quenstedt, pi. xliv, fig. 16, from the Lettenkohle of Gaildorf, which from 

 its shape would appear to be Naiadites.) 



1853. Isaac Lea, in his paper " On some New Fossil Molluscs in the Carbo- 

 niferous Slates of the Anthracite Seams of the Wilksbarre Coal-formations," 

 published in the ' Journal of the Academy of Natural Science of Philadelphia,' 

 ser. 2, vol. ii, pt. 3, January, 1853, p. 203, pi. xx, figs. 1 and 2, describes and 

 figures two new species of Modiola. M. Wyoming ensis and M. "minor, which 

 occur with shells, which he provisionally places under Posidonia, and certain fish 

 remains. M. Wyoming ensis has apparently all the external characteristics of 

 Naiadites, and, indeed, Lea compares his shell with Modiola (Naiadites) carina fa, 

 Sow. The figure of M. minor is that of a shell too fragmentary for comparison. 



1854 and 1856. In 1854 McCoy (' British Paleozoic Fossils,' by A. Sedgwick 

 and F. McCoy, p. 514) proposed the name Garbonicola for the Coal-measure 

 Unios. Referring to King's proposed name Anthracosia, but supposing that 

 King had given up his intention to make use of it (as he had not published 

 anything further) McCoy gave a description. 



