442 Mr. T. Davidson on the Brachiopoda. 



added it to Mr. Cuming's unique collection of recent species. 

 Messrs. M'Andrew and Barrett have also informed me that 

 during their two months' dredging along the Norwegian coast 

 last summer they never had the good fortune of seeing it, 

 although much looked for, while Waldheimia cranium (fig. 2) 

 was obtained several times during that period. I therefore 

 thought it useful to figure this interesting form, which presents 

 more than ordinary interest on many accounts. 



It appears the reverse of Terebratula biplicata, having the 

 biplication on the larger or ventral valve instead of on the dorsal 

 one, as in Brocchi's species. It also approaches much in shape 

 to some fossil oolitic species, and especially to one termed Leu- 

 froyi by M. E. Guerange in his 'Repertoire Palseontologique 

 du Dep. de la Sarthe" (1853). 



It resembles also somewhat the figures of the Ter. septata of 

 PhiUppi (Mon. Sicil. ii. p. 68. t. 18. p. 7, 1844), and Prof. O. 

 Schmidt moreover states that he believes he met with it during 

 his dredgings at Oexfjord in 1850. 



6. Terehratella Spitzhergensis, Dav. 1852. PI. X. fig. 3. 



A description of this shell was published in the Proceedings 

 of the Zoological Society of London for May 25, 1852, but the 

 illustrations were omitted. I therefore avail myself of this op- 

 portunity to repair that deficiency. 



Shell ovate, slightly pentagonal, longer than wide; valves 

 almost equally convex; beak produced, incurved, and truncated 

 by a middle-sized foramen ; deltidium in two pieces, partly sur- 

 rounding the aperture ; beak-ridges not very sharply defined ; 

 smaller valve slightly depressed near the front ; surface smooth, 

 strongly punctate, and marked by a few concentric lines of 

 growth ; colour light yellow ; apophysary system composed of a 

 central longitudinal septum, extending to a little beyond half 

 the length of the shell, in the form of a narrow plate somewhat 

 elevated at its extremity, to which and to the hinge-plate are 

 attached the calcified riband-like reflected lamellae forming the 

 loop. Length 4, width 3, depth 2 lines. 



Hab. Spitzbergen. 



Obs. This small Terehratella seems distinguishable from all 

 the other recent forms of the genus, by its dimensions, regular 

 ovate shape, thinness of shell, and comparatively short doubly 

 attached loop, which does not exceed half the length of the 

 valve. I have hitherto been able to examine but one specimen, 

 presented by R. M' Andrew, Esq., to Mr. Cuming's collection. 



