358 GENERAL SUMMARY TO 



What Dr. "Waagen states with respect to the biplicate Terebratula is quite correct, 

 and this difficulty is equally felt in connection with species belonging to many of the 

 other groups. It is quite true likewise that it has been found necessary to divide the 

 large family Terebratulidce into a certain number of groups or sub-families, each 

 group being composed in the present state of our information of one or more genera ; but 

 palaeontologists are as yet far from having agreed in every case as to the genera that 

 should constitute each sub-family. 



M. H. Douville, Prof. Zittel, 1 and some others would, I fear, feel disposed to admit a 

 larger number of sub-families and genera than I might consider desirable ; but as this is 

 a matter of opinion, I do not wish to press my own personal views in opposition to theirs, 

 which may perhaps after all be the most correct. 



For instance, M. H. Douville, in his interesting memoir, ' Sur quelques genres de 

 Brachiopodes {Terebratulidce et Wald/ieimiidce),' 2 proposes to admit the following eight 

 genera (viz. Terebratulina, Terebratula, Liothyris, Dictyothyris, Glossothyris, Pygope, 

 Dielasma, and Ccenothyris) into his family Terebratulidce. On these I would make some 

 remarks bearing upon their loops. 



1st Genus. — Terebratulina, d'Orb., 1847; type T. caput-serpen lis, Linne. 

 In this genus the loop is rendered annular by the union of the oral processes. 



2nd Genus. — Terebratula, Llwyd (1699) and Klein, 1753 (' Tentamen Methodi Ostra- 

 cologicae,' p. 171, pi. 11, fig. 74), type Anomia Terebatula, Linne. 



Loop short, rarely attaining a third of the length of the dorsal valve, and formed of 

 two short branches connected anteriorly by a more or less arched and not reflected 

 lamella. This lamella varies a good deal in size in different species. In T. uva, T. 

 vitrea, T. carnea, T. Cubensis, T. subquadrata, and in some Tertiary species, it is small, a 

 little larger but similar in character in Terebratula biplicata, T. sub-sella, T. ampulla, T. 

 grandis, &c. 



For the first lot of above-named species M. Douville proposes the generic name of 

 Liothyris, for the second that of Terebratula, Klein ; but, as they all pass one into the 

 other and possess the same general characters, the dividing them into two genera seems 

 to me perfectly unnecessary and only complicates the nomenclature for no serviceable 

 purpose. 



The first notice I can discover of the word Terebratula is in the first edition of 

 Llwyd's book, ' Lithophylacii Britannici Ichnographia,' p. 40, 1699, where he says: 

 — " 827. Terebratula flabelliformis nigra, gibbosa major. In lapicidinis Witneiensibus 

 invenimus, sed rarissime. Est auteni Terebratula conchites Icevis Trigonellce congener ; a 

 per/oralo [utplurimum) rostro, sic dicta." Llwyd in his plates 10 and 11 gives figures of 



1 « Handbucb. der Palaeontologie,' pp. 643 to 722, 1880. 



2 ' Bull. Soc. geol. de France,' 3rd ser., vol. vii, p. 251, 1879. 



