40 DR. T. DAVIDSON ON EECENT BEACHIOPODA. 



the crural processes are separated in the young, arched in tlie adult. Colour dirty white. 

 Length 4, lireadth 3, depth 2 lines. 



Obs. This small shell was discovered by T)r. J. Gwyn Jeffreys, who described it as a 

 small or young specimen of TerebraUila, which he had obtained during the ' Porcupine ' 

 Expedition in 1870, at a depth of 795 fathoms; and he adds that Prof. Loven bad lent 

 him a perfect example from the Josephine Bank off the Straits of Gibraltar, di-edged iu 

 340 to 430 fathoms. Since then several larger and more adult examples were also 

 obtained by the French dredging expeditions in 1882 and 1883, off the western coast 

 of Africa, at a depth of about 4787 metres, and off Morocco and Sahara (' Talisman ' 

 Expedition), in 300 to 1261 fathoms. 



25. Teeebratulina teigona, Jeffreys, sp. (Plate VI. figs. 21, 22.) 



Terebratula trigona, Jeffreys, Mollusca of the 'Lightning' and 'Porcupine' Expeditions, 18fi<S-70, 

 Proc. Zool. Soc. 1878, p. 402, pi. xxii. fig. 3. 



Shell small, ovate, broadly rounded anteriorly, tapering posteriorly, moderately 

 convex, semitransparent between the ribs and glossy ; beak short, foramen rather 

 large, incomplete, lateral deltidial plates small ; hinge-line obtusely angular. Sur- 

 face of the valves marked by about eleven simple rounded ribs, of which the three 

 central ones are the largest. Coecal tubuli numerous. Margins gently curved and 

 scalloped in front. Surface of valves marked with numerous equidistant raised lines. 

 Loop short, simple, and semicircular. Colour clear white. Length scarcely 2 lines, 

 breadth 1 i. 



Obs. We know so very little about this so-called species that its specific claims cannot 

 ])e substantiated. I have only seen a single living specimen, that dredged by Mr. Saville 

 Kent in Marshall Hall's yacht ' Noma' off the coast of Portugal, in about 500 fathoms. 

 Dr. J. Gwyn Jeffreys, who described the shell in 1878, says : — " It may perhaps be 

 immature ; but I cannot identify it with the young of any other species." In this I 

 feel disposed to agree with Mr. Jeffreys, as I examined the specimen with great 

 attention while drawing the figures for his paper. 



Genus WALDHEIMIA, King, 1850*. 



This excellent genus was founded in 1850 by Prof. AV. King for those Terehratulce 

 in which the dorsal valve was jn-ovided with a long deeply reflected loop, having its 

 crura attached to the hinge-plate, as is seen in the recent type Terebratula jlavescens, 

 Lamarck. In the same year Prof. King proposed a genus Macandrevia for a shell with 

 a similar loop, in which the umbonal cavity of the ventral valve is furnished with two 

 dental plates, passing somewhat perpendicularly from tlie dental prominences to the 

 surface of the valve, the umbonal cavitv in the dorsal valve lieing also furnished with 



o 



* In 1840, four years jirior to the p\ililication of King's name WaJdheimia for a Eraohiopod, the same name had 

 heen given by Brulle to an insect ; and both Prof. J. Hall and E. Deslongchamps question whether it can consequently 

 be retained for a Brachiopod, 



