SPIRIFERA. 27 



Cambridge Museum we find the species, both labelled and described by Professor 

 M'Coy as JSp. recurvatus of Professor De Koninck. For a long time I considered 

 the Belgian form last named to be synonymous with the British species, but am positively 

 assured by Professor De Koninck that they are distinct ; and that, although both are 

 found in Belgium, they do not occur in the same beds. The characteristic shape of the 

 adult shell is represented by figs. 26, 27, 81, and 35; fig. 26 being drawn from one of 

 Professor Phillips's typical examples in the British Museum ; fig. 31 is from another in his 

 own collection. The specimens selected for illustration exhibit the different aspects and 

 character of striation presented by this species, and it will be observed that in the young 

 state (fig. 36). and often even up to an advanced age (fig. 33), the regular convexity of the 

 valves is undisturbed by either sinus or fold, both valves being covered by numerous 

 slightly produced stria?. In other examples (figs. 26 and 35) a distinct, narrow, and obscurely 

 defined flattened fold is visible ; a sinus in the opposite valve being also perceptible, 

 which is, however, deeper in some exceptional examples (fig. 28). These variations 

 have their influence on the frontal wave, which is at times hardly perceptible ; while at 

 others, as in figs. 31 and 38, it is clearly defined. The number of ribs is also very variable, 

 being smaller or larger according to individuals, and increased by intercalation. I have 

 counted from thirty to thirty-eight round the margin of the smaller valve, four or five 

 occupying the place of the fold where such is regularly defined. 



In the ' Synopsis of Carb. Fossils of Ireland/ Professor M'Coy states — " It appears to 

 me that this species {Bracliytltyris planata) is the shell intended by Martin as his Anomites 

 rotundatus, and not Spirifer rotundatus of Sow." This is, however, a mistake, as the 

 young of rotundatus is certainly that of the species of which Sowerby published the adult 

 at a later period, and does not possess the character of planata of Phillips. Professor 

 M'Coy gives to his Irish specimens the dimensions of 1 inch in length and width, which 

 surpasses that of any of the numerous English examples I have been able to examine. 

 M. Semenow has also fallen into the same mistake. 



Loc. Common at Bolland, whence Professor Phillips obtained his types. Those 

 in the Cambridge Museum are labelled Derbyshire. It occurs also at Settle, in 

 Yorkshire, as well as in the Isle of Man (Dr. Cumming). Mr. Kelly quotes Bundoran, 

 Ardclogh, and Little Ireland, as the Irish localities. I am not acquainted with any 

 Scotch example. M. De Koninck has it from Vaulsort, near Dinant, in Belgium. 



SriitirERA triangularis, Martin, sp. Plate V, figs. 16 — '24. 



Conchyliolithus anomites triangulakis, Martin. Pet. Derb., pi. xxxvi, fig. 2, 



1809. 

 Spirifer triangularis, Soiverby. Min. Con., tab. 562, figs. 5, 6, May, 1827. 



— — Von Buck. Mem. Soc. Geol. de France, vol. iv, p. 182, 



pi. viii, fig. 5, 1840. 



