I90I S. S. BUCKMAN — BRACHIOPODA 243 



Two fimbriate Terebratuloids have now been noticed, 

 Pscudoglossothyris simplex and Terebr. polyplccta. To 

 the latter is related T. plicata as direct parent, to the 

 former Ps. galeiforniis, var., Mr Upton's shell, as not 

 quite a direct descendant. There remains another series, 

 T. Jivibria, collateral of T. polyplecta, though not derived 

 actually from T. plicata. The fiinbria series commences 

 in the Pea grit {^Miirchisonce hemera) probably a little 

 later than T. plicata. It has two characters pointing to 

 its close connexion with that fossil — first, a somewhat 

 obliquely truncate beak, such as characterizes the plicata 

 stock all through ; secondly, a circular shape, which charac- 

 terizes only the young T. plicata. But its independence 

 is seen in this : it does not wait to become elongate before 

 it is fimbriate ; it becomes fimbriate while still circular. 



Then the next stage is seen in the Oolite Marl (^Brad- 

 fordensis hemera.) The beak has developed ; it is not 

 obliquely truncate, but it curves over the umbo some- 

 what. And the development of the fimbriae has been 

 accelerated — they appear earlier and become more pro- 

 nounced. 



The third stage is seen at a later date — the Upper Free- 

 stone (later Bradfordensis hemera.) The earlier inherit- 

 ance of the fimbriae has become so marked that Httle of 

 the original smooth shell is seen : the fimbriae begin in 

 early immaturity. And in immaturity elongation takes 

 place ; so that somewhat the shape of Terebr. polyplecta 

 is simulated. But as iki^ fimbria stock in its second stage 

 of development — in the Oolite Marl — becomes possessed 

 of the curved-over beak, it has in its third stage a character 

 of distinction, no matter how much it may simulate 

 another shell. The curved-over beak, in fact, is the 

 character : it is a further development than that of T. poly- 

 plecta ; but that fossil had not acquired it when elongate. 

 The T. fimbria series does so before becoming elongate. 



