102 DE. T. DAVIDSON ON EECENT BRACHIOPODA. 



Shell small, ovate, longer than wide, hroadest and rounded anteriorly, tapering 

 posteriorly. Dorsal valve very gently convex, somewhat compressed, with about 16 or 

 17 rounded radiating ribs of small elevation on both valves, commencing to rise at about 

 one third the length of the valves, the beak and umbo being smooth. Ventral valve a 

 little deeper than the dorsal one ; beak slightly incurved and truncated by a large incom- 

 plete foramen, margined posteriorly by the umbo of the dorsal valve, and laterally by 

 small deltidial plates. Shell-structure punctate. Colour waxy or ash-grey. Length 

 3 lines, breadth 2| hues. 



Sab. PopoflF Strait, Shumagin Island ; one specimen, with Magasella aleutica, adhering 

 to stones at the lowest tides (Dall). 



Ohs. In 1877 Mr. Dall did not figure his species, but subsequently, in 1885, he sent me 

 the enlarged figure, wliich I have much pleasure in reproducing, and writes : — " The inside 

 is like that of the ordinary Magasella form. I did not like to open my only specimen to 

 get it drawn. I have young Terehratella transversa {^caurina) less than half the size, 

 which show the imperfectly formed but still genuine Terehratella loop ; hence I cannot 

 ascribe this to the young state of that species, and as we have no other radiated form in 

 Alaska yet known, I am at a loss to name an adult form from it." 



60. Magasella labkadoeensis, Sowerby, sp. (Plate XVI. figs. 18, 18 a.) 



Terebratula Labrador ensis, G. B. Sowerby, Proc. Zool. Soc. 1846, p. 95, and Thes. Concli. i. p. 362, 

 pi. 71. figs. 89, 90, 1846. 



Terebratula {Terebratella) Labradorensis, Sowerby?, L. Reeve, Conch. Icon. Monogr. Ter. pi. v. fig. 19, 

 1860, and Ann. & Mag. Nat. Hist. 3rd ser. vol. vii. p. 178, 1861. 



Terebratella Labradorensis, Dall, Proc. Acad. Nat. Sci. Philadelphia, 1873, p. 185. 



" Shell suborbicular, acuminated behind, obtuse, thickish, whitish ; valves very uueqiial, 

 obtusely radiately ribbed : marginal line somewhat flexuous ; dorsal valve rounded in 

 front, acuminated and obtuse behind ; perforations large, entire ; cardinal area large, 

 somewhat flattened ; deltidia rather large, united ; mesial ridge indistinct ; ventral valve 

 nearly orbicular, slightly acuminated behind : margin of valves crenulated. — In the 

 British Museum. Erom Labrador; C. Goodsir." (G. B. Sowerby.) 



Obs. I know so little about this doubtful species, that I am obliged to content myself 

 by reproducing Sowerby's description, in the hope that a search for more specimens 

 may be effected in the locality whence the shell is said to have been obtained. In the 

 ' Conch. Icon.' LoveU E-eeve figures another species from Cuming's collection, said to 

 agree with Sowerby's type ; but I cannot help regarding this statement as very uncer- 

 tain. The sheU is more circular than the specimen figured in the ' Thesaiu'us Conchy- 

 liorum,' and is stated to be " a rather depressed transparent white orbicular species, of 

 solid structure, ribbed with more strength and regularity than is common in the genus." 

 1 have written to gentlemen who have dredged in Canadian waters, but none of them 

 have ever met with the shell. 



