503 Geological Society. 



It is pointed out that this name is pre-Linncan, and can only date 

 from the time when it was revived by L. von Buch in 1834. Prior to 

 that several names had been given to these shells. The tirst were Tere- 

 hrntula cor and 7'.^j?7cj(s given by Bruguiere in 179:2 in the 'Journal 

 d'Histoire >< aturelle,' his paper in which has been entirely overlooked 

 by workers on these shells. Uruguiere's names indicate a perforate 

 and an imperforate species respectively. Consideration is then 

 given to the synonymy of certain diphyoid species : — T. triangulus, 

 Valenciennes, in Lamarck, which was actually founded on Bruguiere's 

 own figures of his T.pileas ; T. friquctra, Parkinson, which includes 

 two species, a perforate and an imperforate ; and 2\ antinomin, 

 Catnllo, which covers various species. These and others all antedate 

 T. dijilnja, L. von Buch. 



It is pointed out that Terehratula diphya is not the type of the 

 genus Fii(iope, as all text-books say ; for Link, the author of the 

 generic name, referred onlj' to T. antinomia, Catullo. Reasons ai"e 

 given for taking as the type of Pucjope one of the forms of T. antinomia 

 which is considered to be the same species as T. deltoidea, Val. 

 Then the later generic name Antinomia, Catullo, is discussed. 

 The genus was founded on five species ; and one of them is now 

 selected as the type — the genolcctotype. This is A. dilatnfa, Catullo, 

 supposed to be equivalent to Terehratida rt/(^ino?»?rt, Catullo, that is, to 

 what is now selected to be the type of that species. In that case the 

 species would bear the name Antinomia antinomia (Cat.). The two 

 generic names Pijijope and Antinomia are employed, because they are 

 sui)posed to indicate two independent parallel genetic scries, whose 

 members differ in size and position of the perforation, and in 

 characters of the lateral margin. But there is yet another series 

 of diphyoids, typified by Terehratula d.iphyoides, d'Orb. It is pointed 

 out that, although the species covered by the name diidu/oides are 

 very like Pj/gope as now used, yet they all differ in having particular 

 characters in the preperforate stage — a dorsal ridge and a ventral 

 sulcus. For this series de Haan's M8. name Pyejites is used ; and 

 it is supposed that there are three genetic series of diphyoids which 

 have developed independently, and that the remarkable perforate 

 iorm, with its two lobes joined, has been evolved three times over, 

 A genetic plate is given, figuring for comparison many of the species 

 in the three series, showing their development from the glosso- 

 thyridoid, to the bifidate, to the perforate (ordinary T. dijJiya) stage; 

 and that then they finish by losing all trace of the perforation, the 

 lobes completely coalescing (the imperforate stage), represented by 

 Terehratida piltus, Biug. = r. irianjulus, Val. in Lamarck. 



Synonymies and short notices of the species in the three genera 

 have been given. In compiling them there have been found two 

 papers overlooked by Brachiopod bibliographers — one by E. Newman 

 in the ' Zoologist ' naming T. Duvali, and one by Catullo. 



