SPIRIFERIDtE. 



131 



a rounded wave. Surface of valves covered with numerous, small, radiating, rounded, 

 irregularly bifurcating ribs, which increase in width and number towards the margin, and 

 are separated from each other by concave sulci of rather less width ; the valves are also 

 crossed at greater or less intervals by numerous foliated expansions, rising from the 

 surface of the valve and projecting in different specimens from two lines to nearly an inch 

 from the sm-face and margin of the valves. On these foHated expansions the rounded 

 ribs and concave interspaces, which occiu* upon the valves, are regularly continued. 

 Shell-structure fibrous and impunctate. In the interior of the dorsal valve is a divided 

 hinge-plate, supporting two broad spirally coiled lamellse ; spires vertical, closely appressed 

 and directed towards the disk of the valve. A largish specimen, with its foliated 

 expansions, measured — 



Length 26, width 31 lines. 

 Obs. At page 54 of my Devonian Monograph this species has been described at 

 some length, and to that work the student is referred for details respecting muscular and 

 other impressions. We will now add some further remarks in connection with the 

 Silurian specimens. First of all, with reference to the specific name, let me observe 

 that natm'alists appear to be now very generally agreed that the single specific denomina- 

 tion of reticularis, given by Linne, in the Twelfth Edition of his ever-memorable 

 ' Systema Naturae,' should replace some nine or ten other names subsequently given to 

 modifications of this very variable and far-spread species. Linne informs us that his 

 shell is heart-shaped, and marked with decussate striae ; the shorter (dorsal) valve more 

 gibbous than the other ; and the beak of the flat valve slightly prominent. He moreover 

 refers us for a description and figure to p. 88, PI. V, fig. 5, of his ' Musseum Tes- 

 sinianum' (pubhshed in 1753); but 1 must confess that it would be difficult to 

 recognise the Anomia reticularis in the two badly drawn figures given of the shell in 

 question. The description, however, is somewhat more to the point. ^ 



At page 65 of his memoir entitled 'Petreficata Tellmis SuecanEe,' in the eighth 

 volume of the 'Nova Acta Regiae Societatis Scientiarum Upsaliensis,' published in 1821, 

 Wahlenberg gives a short description of the shell under discussion;^ and a perfectly 

 recognisable figure of the Linnaean shell will be found in PI. 450, fig. a, 8, of Martin 

 Lister's 'Historia sive Synopsis Methodica Conchyhorum,' &c., published in 1688. 



' "/3. Anomia subrotunda striis loDgitudinalibus viginti. Tab. v, fig. 5. 

 Testa subrotunda, parum compressa, striis longitudinalibus. Figs. 20, 21. 



Valvula superior antice in medio convexa, eraarginata. Valvula inferior, natice in medio depressa, 

 elongata, adscendens umbonum alter postice prominet." 



2 " b. Anomites reticularis, superficie reticulata (vel decussatim nervata), valvulis undique aequabiliter 

 convexis, breviore convexiore, Gmel. Syst. Nat., i, p. 3343 (excluso Synoa. Linnseano et A. plicatellam 

 pertinente). Fischer, Program, de Terebrat., p. 31, n. 19, t. iii, fig. .5. Schroet., AbhandL, vol. ii, t. iii, 

 figs. 11 — 14. Frequenter in Gotblandia occurrit. Superficie margaritacea splendente insiguis : impres- 

 siones autera in Sebisto superiore Westrogotbise passim conspiciuntur." No one, 1 think, could recognise 

 in Fischer de Waldheim's figure the Anomites reticularis of Linnseus. 



