Yol. 62.] BRACHIOPOD H0MO20M0RPHY. 441 



possess no trivial names by which they can be referred to. Therefore 

 in the works noticed in the Bibliography (p. 451) are many figures 

 of diphyoid forms not mentioned in the following pages. 



Genus Antinomia, Catullo, 1851. 



Genosyntj'pes — A. diphya, A. deltoidea, A. angulata, A. dilatata, A. angusta. 

 Genolectotype — A. dilatata, Catullo= Terebratula antinomia, Catullo. 



A series of diphyoid Terebratulids in which the perforation (when 

 present) is small and set close to the umbo, while the sides of the 

 valves are flattened, and the side-margin is much curved. 



Glossothyridoid Stage. 

 Antinomia plaxulata (Zeuschner). (PL XLI, fig. 1.) 



Terebratula planulata, Zeuschner, 1846, teste Zittel. T. planulata ; 1 Zitte , 

 1870, pi. xiv (xxxviii) tigs. 3, 4, 5. T. diphyoides ; Quenstedt, 1871, pi. xlvii, 

 figs. 121 & 122. T. dipJwros ; Quenstedt, 1871, pi. xlviii, fig. 1. 



According to Zittel, this form has been named T. planulata by 

 Zeuschner in the work which is not obtainable. 



This form, which is more transverse than Glossotliyris nucleate^ 

 shows a similar deep sulcus in the anterior part of the dorsal valve, 

 giving the front margin a linguiform appearance. The arrest of 

 growth in the linguiform portion, and the expansion of the lobes 

 on each side of it, produce the bifidate form. 



Bifidate or Binate Stage. 2 



Antixoaiia sima (Zeuschner) 1846, teste Pictet. (PI. XLI, fig. 2.) 



Terebratula sima, Zeuschner, 1846 (Pictet). T. sima; Pictet. 1867, pi. xxxiii, 

 figs. 4 & 5 only. T. sima ; Zittel, 1870, pi. xiii (xxxvii) figs. 11 & 12. 



A form with long lobes, and a remarkable curved side-margin. 



Antixomia diphora (Zeuschner) 1846, teste Quenstedt. (PI. XLI, 

 fig. 3.) 



Terebratula diphoros, Zeuschner, 1846 (teste Quenstedt). T. diphya; Pictet, 

 1867, pi. xxxi, fig. 8. T. dipJwros; Quenstedt, 1871, pi. xlviii, fig. 6 only. 



Whether this is really Zeuschner's species is doubtful, nor can it 

 be said if Pictet's form agrees with what Quenstedt calls diphoros, 

 because the latter shows no side view. What Pictet shows differs 

 from A. sima by its less curved margin. 



According to Pictet and Quenstedt the following other species 

 were named by Zeuschner: — T. rogoznicensis, T. accine, T. expansa, 

 and T. Staszicii : and it seems that all except the last one are bifidate 

 forms. 



1 When the author cited is the giver of the trivial name a comma is used ; 

 when he is not, a semicolon. 



2 A leaf with two lobes is known in botany as ' binate ' (folium binatum). 



