BuCKMAN. — T erminology for Brachiopoda. +53 



and for ornament afterwards. It is sure to be said tliat one siiould take 

 the Greek word of similar meaning — x^'^'^ — ^^^ write " chalicotliyrid " ; 

 but I am not in favour of this far more cumbrous and less obvious word. 

 The Craniidae, Thecidiidae, and Richthofenidae are some of the cemented 

 shells and are therefore calcithyrid. If it is urged that the development 

 in the last-named is so much greater that it deserves distinction, then I 

 make it a present of '' chalicothyrid " : it does seem rather to suit that 

 family. 



The above terms would seem to provide a ready means of describing 

 some important aspects of beak and foraminal development. But there 

 is a further case to be considered — the position of the foramen in shells 

 which have considerable development of the cardinal area or its homologue 

 the false cardinal area. Two terms for what is reallv the same feature 

 are very unsatisfactory. There is some objection to calling this feature 

 simply '' the area," for that term is rec[uirecl for general use; but it might 

 be termed the iitlerarea, as being the area lying between the apex and 

 the posterior line of valve-junction — the cardinal margin when there is a 

 hinge, but at any rate the posterior margin When there is lateral com- 

 pression posteriorly by which areas are formed each side of the beak- - 

 shown, for instanc<\ so well in EhynclioneUa plicafella — then the term 

 " areola," which is in use, seems unsuitable ; for it is larger, not, as its 

 name suggests, smaller, than the cardinal area. The term planarea seems 

 advisable. There would thus be the interarea and the ])lanareas ; but the 

 presence of the one would, I think, prevent the other appearing in the same 

 shell : at least, the former is merged in the planareas. 



With great development of the interarea the term '" liy[)othyrid " for 

 the position of a foramen in the interarea might not be sufficiently precise. 

 It could be modified as "apically," "medianly," or " marginallv " hvpo- 

 thyrid, as the case might be. 



Mention of the apical position suggests that it is desirable to distinguish 

 the rostrate shells which keep the apex and those which lose it : the 

 former, like the Rhynchonellidae, would be shells with rostrum apicate ; 

 the latter, like Terebratuloids, with rostrum truncate. It has been iLsual 

 to speak of the foramen as being truncate ; but this is mainly from 

 a consideration of the attrite foramen of the Terebratulids. But the 

 attrite condition is expressive of the wearing-away of the tela — the points 

 of the beak-ridges ; and so it seems advisable to apply the term 

 " truncate " to the rostrum as soon as the apex is excavated by the 

 pedicle. The angle and the degree of such truncation, especially when 

 combined with attrition, may vary very considerably — obviously through 

 nearly 180 degrees. To meet such cases " subtruncate " or " undercut," 

 " vertically," " obliquely," and " horizontally " truncate might suffice for 

 general purposes. Words compounded of in and re are to be avoided ; 

 for properly the latter should apply to what goes backwards — that is, 

 towards the dorsal valve. Too often the former has been used for such 

 cases — the legacy of old teaching. Peccavi! 



One other point is for consideration. When the pedicle has eaten 

 through the apex and has attained the epithyrid position, or even before, 

 it seems to have a tendency to return — to move back towards the dorsal 

 valve again : it may be said to be in character remigmnt. In such case 

 it produces a labiate foramen with some recutting of the dorsal wall of 

 the foramen. In such recutting points might be produced which resemble 

 tela but are not true ends of beak-ridges, only projecting edges of foraminal 



