148 Zoological Society. 



arising from under the cardinal process and crural base, by a gentle 

 curve reaches and touches the larger valve near to its anterior portion, 

 from whence it descends by an almost perpendicular line to the bottom 

 of the valve ; the calcareous riband-shaped lamellae first proceed from 

 the socket walls, directing themselves by a gentle curve to the ante- 

 rior portion of the septum, to which they become attached before 

 bending on themselves to form a loop ; the arms are of a brilliant 

 red colour. Length 5, width 4, depth 2^ lines. 



Hab. New Zealand. Coll. Cuming. 



Obs. — Two specimens of this remarkable shell have been obtained 

 by Mr. Cuming, and it is one of the most interesting among the re- 

 cent forms, presenting great difficulties from an assemblage of cha- 

 racters peculiar to more than one of the proposed sections. In out- 

 ward shape, character of its foramen, and interior of perforated valve, 

 it much resembles Bouchardia rosea ; its foramen is likewise very 

 similar in position to that presented by several species of Trigonose- 

 mus ; the shape and position of its central elevated septum, which 

 touches a portion of the centre of the larger valve, relates it to Magas, 

 and the disposition of the lamellae to Terebratella. I therefore do 

 not feel certain in what genus this curious shell should be placed : it 

 is not a true Terebratella, but there I have placed it for the present, 

 on account of the form of the loop. 



iiiqifiOt* 



5. Terebratella Spitzbergensis, Dav. 1852. .xnsto 



Diagnosis. — Shell ovate, slightly pentagonal, longer than wide ; 

 valves almost equally convex ; beak produced, recurved, and truncated 

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

 ing 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, ex- 

 tending 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-shaped lamellae form- 

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



Hab. Spitzbergen. 



Obs. — This small Terebratella 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, from the collection 

 of Robert M*Andrew, Esq., and Mr. Cuming. '- 



6. Terebratulina Cumingii, Dav. 1852. 



Diagnosis. — Shell ovate, somewhat pentagonal, nearly as wide as 

 long ; valves almost equally convex ; beak small, obliquely truncated 

 by a circular emarginate foramen ; deltidial plates disunited, a small 

 portion of the aperture being completed by the umbo ; auricular ex- 

 pansions on either side of the umbo very small ; surface ornamented 

 by a great number of minute radiating elevated strise, augmenting 



