170 BRITISH SILURIAN BRACHIOPODA. 
Collection he found the box of Axomia lacunosa containing four specimens which would 
agree with Zerebratula Wilsont. 
I need not refer to Schlotheim’s interpretation of Z. Jacunosa (‘Die Petrefact.,’ 
p. 267, 1820), further than to say that he unites under that denomination a strange 
mixture of different species. In 1834 Von Buch (‘ Ueber Ter.,’ p. 47) adopts Sowerby’s 
T. Wilsoni, placing at the same time Wahlenberg and Dalman’s 4. dacunosa among 
its synonyms; he also mentions that the Zer. /acunosa of Zeiten and of Schlotheim 
is a distinct species from that of Linnaeus; and adds, “It is sufficiently evident, from 
the figure of Fabio Colonna,’ and his description, that in his Anomia triloba lacunosa 
he has wished to refer specially to this (Jurassic) Terebratula, and that Langé and 
Scheuchzer have confounded no other shell with this one; that in all likelihood Linné 
wished to reunite under the name of Jacunosa all the Terebratule of which the dorsal 
(ventral) sinus is distinguished by an upper plaited surface ; and that, consequently, when 
the Swedish naturalists wish to reduce this denomination to the Z. Wilson, they have not 
the right to invoke for this the authority of Linné.” I cannot, however, entirely coincide 
with the baron’s view, although the various references to the figures given by Linné for 
his 4. dacunosa might lead to that inference; for it must also be remembered that Linné 
describes other Anomias referable to other species of Rhyuchonella. Bronn, in his ‘Index 
Paleontologicus,’ adopts Sowerby’s 7. Wilsont, adding A. /acunosa of Linné, Wahlenberg, 
Dalman, and Hisinger, among its synonyms. Lindstrém also, in the ‘ Proceedings of the 
Royal Academy of Stockholm,’ adopts the term /V7/soni in preference to that of dacunosa ; 
so also MM. de Verneuil and Keyserling, at p. 87 of their work ‘On the Geol. of Russia ;? 
and d’Hichwald and many other paleontologists have taken the same view. The 
designation Wi/soni must therefore be adopted for the shell under description, and that of 
lacunosa placed amongst those incerte sedis, or with a point of interrogation among the 
synonyms of /V7i/soni ; for no paleontologist can in justice claim any species as his own 
whose description and figures are as obscure and doubtful as are those of the so-termed 
Anomia lacunosa of Linneus. 
Rhynchonella Wilsont is variable in its shape, but especially in the degree of 
convexity or depth of its valves; the ribs are also smaller and more numerous in some 
specimens than in others; and although these last in the greater number of specimens 
become divided by an indented line (fig. 6c) in their proximity of the margin, this 
character is not observable in every specimen. It has also appeared to me that those 
extremely gibbous specimens, whose depth so greatly exceeds that of their length or width, 
occur principally in the Aymestry Limestone; the Llandovery and Wenlock examples 
being larger, but comparatively less deep or ventricose. Ter. pentayona, Sow., from 
the Upper Ludlow of Delbury, Shropshire, is a young shell of 2A. Wilsoni. Mr. Salter 
informs me that the Hemithyris pentagona, M‘Coy (‘ Brit. Pal. Foss.,’ p. 205), is 
1 «De Purpura,’ p. 35, 1675. 
ee 
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