250 Dr. J. G. Jeffreys on some new 



XXII. — On some new and remarhable North- Atlantic 

 Brachiopoda. By J. GwYN Jeffreys, LL.D., F.R.S. 



Among the zoological results of my cruise in H.M.S. * Valo- 

 rous ' last year, on the return voyage from Davis Strait, were 

 three Brachiopods, dredged in deep water, which require 

 special notice. A description of them is subjoined. 



Terebratula tenera *, Jeffreys. 



Shell uniformly oval, with the broader end in front, com- 

 pressed, of a thin and delicate texture, and of a dullish hue : 

 sculpture slight, curved and parallel lines of gi'owth, besides 

 numerous minute tubercles which cover all the surface and 

 are the cjecal terminations of the permeating canals : colour 

 yellowish bro^vn : margins even, rounded in front, and curving 

 gradually behind : heah short, not prominent : foramen or 

 byssal passage small, semioval, incomplete on the inner side : 

 deltidium slight and delicate: Innge-plate broad and propor- 

 tionally strong : teeth in the upper (or more convex) valve 

 short and ciu'ved : skeleton or apophysis in the lower (or 

 smaller) valve consisting of two thin and flexuous blades, 

 Avhicli are slenderer and approximate more than in T. cranium^ 

 but have similar spurs and points ; the loop is horseshoe- 

 shaped : inside of lower valve furnished with two short ridges, 

 which extend on each side from the deltidium, witli a slight 

 septum between and below the ridges. L. O'o, B. 0*4. 



Lat. 56° 11' X., long. 37° 41' W., 1450 fathoms, Glohige- 

 rina-oozQ and stones. Two or three perfect specimens, and 

 several valves and fragments. 



This species differs from T. cranium in being only half the 

 size in exact measurement, and consequently one fourth in 

 bulk ; it is of a different shape, texture, and colour, com- 

 pressed instead of convex, having a much shorter beak and 

 smaller orifice, with not half the proportionate number of 

 tubercles ; and the blades are closer together, and do not extend 

 so far towards the front. In the young of each species the 

 comparative number of tubercles and prominence of the beak 

 are distinctly marked j and the septum in the present species 

 is shorter, although conspicuous and gnomon-shaped. 



Atretia t, g. n., Jeffreys. 



Shell inequivalve, triangular, imperforate, of a fibrous 

 texture : heah prominent and pointed, but not incurved : hyssal 

 orifice elongated : hinge-line narrow : skeleton composed of 



* Tcuder. t Imperfurate. 



