ANTHRACOMYA WILLIAMSONI. 101 
was given by Professor Sir G. W. Dawson to a shell then named by him Naiadites, 
but now recognised as Anthracomya (‘Q. J. G. Soce., vol. 1, p. 437, pl. xx, 
figs. 7—10), but of a totally different species from that under discussion. 
Judging from the description and figure of Eichwald’s Anodonta (Modiolopsis) 
tenera, it is possible that it may turn out to be identical with A. Williamson, 
and this author’s description of the form is as follows :—‘‘ Sehr diinn, aber 
weniger flach, sondern eher gewélbt und concentrisch gestreift, das eme Ende 
weit breiter, als das andere mehr zugerundete, der wirbel flach, wenig hevorste- 
hend der schlossrande grade; beide Schalen hingen durch das Schloss von dem 
einen Ende bis zum andern zusammen wie dies bei Anodonten der Fall zu sein 
pflegt ;”” but it is impossible to be certain, without an examination of the shells, 
whether Modiolopsis tenera belongs to Anthracomya Williamsoni or A. Wardi, which 
it seems to resemble in its posterior border. I am strongly of the opinion that 
one of these two species will be found to belong to Hichwald’s form, and in that 
case his name will have the priority. But there is still another uncertainty as 
to the name, for it is also possible that the species under description may be 
shown to be identical with Mytilus (Modiola) Teplofi, Murchison, de Keyserling, 
and de Verneuil, ‘ Paléontologie de Russie,’ vol. ii, p. 318, pl. xix, fig. 17 (1845), 
the descriptions and figure agreeing very closely ; but not having seen the shell 
it is difficult to speak certainly. This name is also prior to that proposed by 
Captain Brown; and should it be found that A. tenera of Hichwald is identical with 
A. Wardi, then, if M. Teplofi be different in any way from 4A. tenera, it may be 
necessary to substitute de Verneuil’s name for that of Captain Brown. LEichwald, 
in ‘ Lethzea Rossica,’ 1855-9, pp. 977 and 978, also gives a good description of the 
shells M. Teplofi and M. tenera, and in almost identical language, so that each 
_ description might well do for the other; in addition both forms are said to come 
from the same locality—the coal-measures of Lissitschanskaya county of the 
Cossacks of the Don. It may be noted here that the form and comparative 
dimensions of A. Williamsoni are very variable. Mytilus Teplofi is said to occur 
in the coal-mines of Lissitchia Balka (Donetz), below the limestone with Spirifer 
mosquensis, but whether the bed is marine or no is not stated. 
Ludwig simply followed Hichwald with regard to Anodonta tenera, but more 
correctly retained his first generic reference. 
I was able to examine the specimen to which Mr. Salter gave the name of 
Anthracomya sanguinolaris in his paleontological notes to the Survey Memoir on 
the country around Bolton. It is preserved in the Museum of the Geological 
Survey at Jermyn Street, and I have no doubt that this shell belongs to the 
species under description. Another member of the genus Anthracomya occurs 
near the same horizon, but in a different matrix. This one, however, I believe to 
be A. Wardi. 
