2 THE BRITISH OONULAET^. 



somewhat resembling an Orthocera, but furnished with imperforate septa, and an 

 inflexion of the lip that nearly closes the mouth." He also described and figured 

 two species, G. quadrisulcata and G. teres. The former was founded on specimens 

 from "Transition limestone" (fig. 4), "Bristol Limestone about the Hotwells " 

 (fig. 5), " Transition Limestone that contains mica from near Keswick" (fig. 3), 

 and "Tronlie Bank near Glasgow" (fig. 6), and is now known to include three 

 different species, while the latter was doubted at the first by its author, and was 

 soon afterwards recognised to be an Orthoceras. 



In 1828 we find the species G. sowerbyi attributed by de Blainville 1 to Defrance, 

 with a reference to the ' Dictionnaire des Sciences Naturelles.' De Blainville 

 reproduced all Sowerby's six figures, and gave no description ; as all attempts to 

 find any account of G. sowerbyi in the ' Dictionnaire ' have proved unsuccessful, 

 Def ranee's right to the species seems to be very doubtful. 



In 1839 Sowerby 2 described and figured a Wenlock Limestone form under the 

 original name, G. quadrisulcata, mentioning, however, that it might be found 

 possible to separate this from the Carboniferous Limestone species, in which case 

 Defrance's name should be adopted for the former. The next new species was 

 found in Ireland, co. Tyrone, and was described and figured by Portlock 3 under 

 the name G. elongata, together with two other species named respectively " C. 

 quadrisulcata, Sow. var. carb." and " G. quadrisulcata, Sow. var. sil." The two 

 figured specimens of the latter belong to two distinct species. The next important 

 reference to the genus is in the ' Gcologie de la Russie d'Europe,' ' where de 

 Verneuil, in the Paloeontological Section, definitely restricted Sowerby's name, C. 

 quadrisulcata, to the Carboniferous species and adopted Defrance's name, C. 

 sowerbyi, for the Silurian species, distinguished by its greater size, compressed 

 form and continuous transverse folds. The description is accompanied by a clear 

 figure, and since this is the first time that the two forms are definitely separated 

 and named, the species G. sowerbyi should be assigned to de Verneuil. 



In 1847 Sandberger r ' published an important monograph on Palaeozoic 

 Pteropods, in which he described and figured fourteen species, including among 

 them the three known British forms, but giving to them new and more descriptive 

 names, which, however, have not been adopted. He also gave a general description 

 of the genus, and a list of those characters upon which he based his specific 

 distinctions. In 1855 M'Coy ° attempted to clear up the confusion in nomencla- 



1 De Blainville, ' Malacol.' (1828), p. 377, pi. xiv, figs. 2 c— e. 



2 Sowerby in Murchison, ' Silur. Syst.' (1839), p. 627, pi. xii, fig. 22. 



3 Portlock, 'Report, Geol. Londonderry ' (1843), p. 393, pi. xxix a. 



* De Verneuil in Murchison, de Verneuil and de Keyserling, ' Greol. de la Russie d'Europe ' (1845), 

 vol. ii, " Paleont.," p. 348, pi. xxiv, fig. 5. 



5 F. Sandberger, " Pteropoda der ersten Erdbildungs-Epoche : Conularia und Coleoprion," ' Neues 

 Jahrb. fur Min., etc.,' 1847, p. 8. 



fl F. M'Coy in Sedgwick's ' Synops. Brit. Palseoz. Rocks ' (1855), pp. 287, 520. 



