I90I S. S. BUCKMAN— BRACHIOPODA 249 



Comparison : — Zeilleria siibcorniUa is somewhat of a 

 homcEomorph. 



Distinction : — From Terebratula Stephani, the short- 

 ness and abruptness of the pUcse. 



Remarks : — This is a distinctly bipHcate form, but its 

 general build shows it to be an independent development 

 separate from either the sphaeroidal stock, or T. withing- 

 tonensis. Not unlikely, it is the parent of the more plicate 

 T. Stephani. Its date agrees with that idea. 



Locality and Stratum : — Dorset, Wyke Quarry, near 

 Halfway House, in the Irony bed. 



Date of Existence : — Blagdeni hemera. 



V. PSEUDOBIPLICATE (BILOBATE) SERIES 

 (The emarginata homoeomorphs.) 



Attention may now be directed to another series of 

 shells, which show development of pseudo-biplication 

 (bilobation,) This series contains some species which 

 have been seriously misunderstood on account of their 

 homoeomorphy ; and the opportunity may now be taken 

 to point this out. Some of the following pages were 

 written several years ago ; but time did not then allow of 

 the work being completed. Perhaps fortunately ; for 

 they come in very well in connection with the subject of 

 this paper. 



The particular character of bilobation is not uncommon 

 among the Magellanidse ; and its independent develop- 

 ment in different stocks is well known. The interesting 

 fact is its occurrence also, though rarely, among Tere- 

 bratulidae. And in some cases the resemblance between 

 the species of the two families with this bilobate front 

 margin is remarkable. 



It is always a matter for regret when any reason 

 compels the changing of the name by which a particular 



R2 



