DE. T. DAVIDSON ON EECENT BKACHIOPODA. 37 



arrived at thr opiniou that it could be generically distiuguislied. Tiic chief ditfereuces 

 are to be found in the shape and character of the beak. " The long narrow form of the 

 deltidium," writes Prof. King, " causes the area to appear as if divided longitudinally by a 

 linear groove ; whch part is at once striking and unique. The foramen, which appears like 

 a notch in the centre of the cardinal edge of the large valve, is made entire 1)y the juxta- 

 position of the cardinal edge of the small valve. The area is well defined laterally I)y 

 each of the sutures whicji separate it from the inilexed sides of the beak. The loop 

 agrees very closely in form and relative size with that of Terebratula vitrea ; perhaps its 

 crural spurs are more produced. The tubuli apjjcar to run in rows, and to be most 

 numerous in the ribs, from which they branch olf laterally towards the furrows." 

 Mr. Dall believes the specimens described by Prof. King to be the young of some species 

 of Terehratid'mu, but the specimens I have in my possession Avould lead me to consider 

 them the adult condition of a very remarkable small species. 



Uncertain Species. 



20. Terebratulina Cumingi, Davidson. (Plate V. fig. 53.) 



Terehratulina Cuminyii, Davidson, Proc. Zool. Soc. 18.12, p. 71), pi. xiv. figs. 17-19; Keeve, Coucli. 

 Icon., Mouogr. of Terebratula, pi. iv. fig. 12, LSGO. 



Shell small, squarely ovate, somewhat pentagonal, nearly as wide as long; valves 

 almost equally convex ; beak small, obliquely truncated by a large incomplete foramen, 

 deltidial plates disunited, a small ])ortion of the aperture completed by the umbo ; 

 auricular expansions on either side of the umbo, very small ; valves rather gibbously 

 convex. Surface ornamented by a great number of minute radiating stria3, augmenting 

 rapidly by the interpolation of smaller riblets at variable distances from the beaks ; front 

 margin in ventral valve forming a convex curve, and slightly depressed near the front. 

 Loop small, annelliform. Colour opaque white. Length 3|, width. 3, dei^th 2 lines. 



Hub. Chinese Seas. 



Obs. Mr. L. Eeeve says that this is " An extremely characteristic well-defined species. 

 The radiating ridges do not all diverge together from the beak ; a new ridge com- 

 mences between each former ridge as the space enlarges to receive it." T. Cuminyi 

 seems to be distinguished from other species of the subgenus by its size and relative 

 width and length, being much more convex and globular. In 1871 (Proc. Zool. Soc.) I 

 thought that T. Cwningi might perhaps be a variety of T. caimt-serpentis, but am now 

 not of that opinion, for having seen a number of specimens of the Little Chinese shell, I 

 found them all to be possessed of the same shape and character. 



In his " Catalogue of the Itecent Species of the Class Brachiopoda ' (Proc. Acad. jS'at. 

 Sci. Philadelphia, 1873), Mr. Dall places T. Cumingi among liis synonyms of T.japonica, 

 but I cannot agree Avith him in this particular. 



21. Teeebrattjlina abyssicola, Adams & Eeeve, sp. (Plate V. fig. 54.) 



Terebratula abyssicola, Adams & Reeve, Moll. Voyage of the ' Saniarang,' p. 72, pi. xxi. fig. 5, 1850 ; 

 L. Reeve, Conch. Icon. pi. iv. fig. 14, 18G0. 



