SPIRIFERA. 21 



that Sp. condor (D'Orb), 1 represents an individual of Sp. attenuata; and. I possess 

 specimens from the same locality as those described by the French author, which 

 entirely agree with the species under description. Professor M'Coy is also of opinion 

 that what he described in 1844 as Sp. clatharata, must be added to the list of 

 synonyms. 



The long hinge-line of Sp. striata distinguishes it from Sp. duplicicostata of Phillips, 

 but to which it is, however, very closely related by several peculiarities, for many 

 examples of Sp. striata present not only similarly bifurcated and intercalated ribs, 

 but these are also at times arranged in clusters, as is generally the case in Phillips's species. 

 The elevation and proportions of the mesial fold varies also considerably, and in some 

 young and middle-aged shells from Millicent it is badly defined ; these last being also 

 much more elongated and spindle-shaped than is commonly the case ; while others 

 are rhomboidal, with or without prolonged cardinal angles. The ribs on the mesial fold 

 present at times (although much more rarely than in Sp. bisulcata) a tendency to divide 

 into three groups separated by deeper sulci ; but, as above observed, all these minor 

 differences so remarkable, in single individuals, are, specifically, of little importance. 



Sp. striata is the largest Spirifer known, and must always be considered as the type 

 of the genus. There are many varieties, but I shall simply allude to the one found 

 at Dovedale, Derbyshire (Plate II, figs. 15, 16), in which the ribs become so narrow 

 and numerous, that one hundred may be counted round the margin of each valve in certain 

 individuals, giving the shell much the appearance of the Silurian Sp. cyrtcsna. 



Loc. This species is found at Castleton, Dovedale, and other Derbyshire localities ; 

 at Bolland, and different parts of Yorkshire. In Ireland Mr. Kelly mentions Ratheline, 

 Millecent, Little Ireland, Lisnapaste, Cornacarrow, Ardclogh, &c. In Scotland it appears 

 extremely rare, for I have not been able to find any well-authenticated example in the 

 different collections I have been able to examine. It seems to be a rare fossil at Vise, in 

 Belgium, but more common at Ratingen. M. De Verneuil found it at Cosatchi-datchi 

 (east of Miask), on the other side of the Oural Mountains ; also at Pos-en-Cavales (Spain). 

 It is one of the most characteristic fossils of the lower Carboniferous limestone, being 

 found in various American localities, such as Yarbichambi, at 4000 metres of elevation, 

 north of La Paz (Bolivia), as well as in the Quebaya Island, in the Sea of Titicaca. M. 

 Marcou obtained it abundantly in the Rocky Mountains, as well as from New Scotland 

 to Vancouver's Island. 



1 'Voyage dans l'Amerique Meridionale,' vol. iv, pi. xlvi, figs. 11 — 15. 



