﻿574 MISS J. DONALD OF GASTEROPODA EEOM [Aug. 1905, 



collection which appear to agree with the few characteristics given, 

 more especially with the nature of the ornamentation: the keels 

 being three in number on the penultimate whorl, and more numerous 

 and closer below on the body-whorl. Although Sowerby's figure 

 and description are so very incomplete, I nevertheless think it 

 advisable to refer Prof. Groom's specimens to this species, as they 

 resemble it more than any other British-described species belonging 

 to the genus. Also they agree very nearly with specimens that I 

 have seen from the Upper Ludlow elsewhere, as well as from the 

 Aymestry Limestone, Wenlock Limestone, and Wenlock Shale, which 

 have been referred to this species. 



They also resemble those identified by Prof. Lindstrom with 

 Turbo car hiatus, Sow., the greater number coming near to his 

 variety (Gyclonema) glabrum, which has fewer additional keels on the 

 body-whorl. 



The name Turbo carinatus seems to have been pre-occupied when 

 J. de C. Sowerby thus named this species in the ' Silurian System,' 

 1839 (p. 612 & pi. v, fig. 28), for J. Sowerby had named a 

 Greensand fossil Turbo carinatus in the ' Mineral Conchology ' 

 vol. iii (1821) pi. ccxl, fig. 3, and Helix carinatus, Sow., had been 

 so called by Honinghaus in 1830 (in the Jahrbuch fiir Min. Geol., 

 <fec. p. 230). 



In 1850, A. d'Orbigny, in his ' Prodrome de Paleontologie strati- 

 graphique ' (vol. i, p. 30) enters this species as Turbo Octavia, d'Orb., 

 1847, He gives no reason for the change of name; but it was 

 probably changed in order to avoid confusion, on account of three 

 different species having been called Turbo carinatus, and two (as has 

 been shown) previous to Sowerby's description of the species under 

 discussion. It therefore seems advisable to adopt d'Orbigny's 

 specific name Octavia, as several succeeding palaeontologists have 

 done. 



There is a certain amount of variation in the number and dis- 

 position of the keels on different individuals, but all agree in 

 having the wider spaces above. Thus, there appear to be at least 

 three, or perhaps four, well-marked varieties. The first, which seems 

 to agree best with the type, has always two and sometimes three or 

 more additional keels below on the body-whorl, as- well as the 

 strong ridge round the umbilicus ; and there are three keels visible 

 on the penultimate whorl besides the sutural keel, the second and 

 third being closer than in the variety glabrum. In the Museum of 

 Practical Geology, London, there is a specimen from the Upper 

 Ludlow near Ludlow that might be referred here ; and there is also 

 •one in the Manchester Museum, Owens College, from the Upper 

 Ludlow of Whitcliff. 



The second resembles this last variety so much, that it is some- 

 times difficult to decide to which a form should be referred ; but 

 there is as a rule only one additional keel, or rarely two, on the 

 body-whorl, and but two strong keels are seen on the penultimate 

 whorl besides the sutural one. This is the most abundant variety 

 among Prof. Groom's specimens, there being about twelve examples, 

 and it is probably the variety glabrum of Lindstrom. Here belong 



