Vol. 62.] BRA.CHTOPOD HOMCEOMORPHY. 445 



Genus Pygope, Link. 



Genosyntypes — Terebratula antinomia, Catullo, 1827, p. 169 & pi. v, figs, p, q,&r. 

 Genolectotype — Terebratula antinomia, Catullo, ibid. fig. r = T. deltoidea, 

 Valenciennes. 



A series of diphyoid Terebratulids in which the perforation (when 

 present) is relatively larger and farther removed from the umbo than 

 that of Antinomia ; while the sides of the valves are not compressed, 

 and the side-margin is practically straight. 



Glossothyridoid Stage. 

 Pygope eupicola, Zittel. 



Terebratula rupicola, Zittel, 1870, pi. xiv (xxxviii) figs. 1 & 2. 



Similar to Antinomia planidata, but broader, as one would expect 

 this stage in Pygope to be. 



Bifidate Stage. 



Bifidate forms, morphic equivalents of A. sima and A. diphora, are 

 to be seen in Pictet [29], pi. xxx, figs. 5-6 & 9-10, and Suess [35], 

 pi. vii (iii) fig. 13 ; see also PI. XLI, fig. 10. Forms with the two 

 wings just coming into contact — the next stage — are shown by 

 Pictet, pl. * xix > fi g' s - 4 & 6 ; see PI. XLI, tig. 11. 



For other figures of Pygope, besides those mentioned here or 

 later, see Pictet, Terebratula janitor • Glocker [19], T. diphya, 

 pl. xxxv, fig. 14; and Gemmellaro [18], pl. i, figs. 1-5. 



Perforate Stage. 

 Pygope janitor (Pictet) 1867. (Pl. XLI, fig. 12.) 



Terebratula janitor, Pictet, 1867, pl. xxx [fig. 2bis] lectotype ; pl. xxx, fig. 1 ? 



Be marks. — As I do not feel able to separate what Pictet calls 

 his type-form from the earlier-named Terebratula deltoidea, and as 

 another of Pictet' s forms is occupied by T. Duvalu an overlooked 

 name, it becomes necessary to fall back on one of Pictet's varieties. 

 If his name is to be preserved, that must be taken as a lectotype. 

 It is a latangulate form, morphic equivalent of Antinomia dilatata. 



Pygope deltoidea (Valenciennes) 1819. (Pl. XLI, fig. 13.) 



Terebratula , Ency. Meth. 1797, pl. ccxl, fig. 4. T. deltoidea, Val. in 



Lamarck, 1819. T. antinopiia, Catullo, 1827, pl. v, fig. 2. T. dipliya, von 

 Buch, 1838 (copy of Ency. Meth.). T. dipliya ; Bronn, ' Leth. Geogn.\1838, 

 pl. xxx, fig. 14 (copy of Ency. Meth. ?). T. deltoidea ; Catullo, 1840;(copy 

 of Ency. Meth.). Antinomia deltoidea; Catullo, 1851 (outline; reduced i 

 after Ency. Meth.). Terebratula janitor, Pictet, 1867, pl. xxix, fig. 5. 

 T. diphyoides ; Quenstedt, 1871, pl. xlviii, fig. 1. 



The specimen which Davidson figured in the ' Annals ' [13] as 

 T. deltoidea (pl. xiii, fig. 20) does not seem to be the same shell as 

 Q. J. G. S. No. 247. 2 h 



