3^0 TESTACEOUS MOLLUSCA. 



** Surface minutely shagreened or punctated ; otherwise smooth. 1 



T. Vitrea.— Anomia V. Born, p. 119.— Gm, 3347.— A. Tere- 

 bratula, D. p. 294.— W. t. 11, /. 23.— T. V. Lam. l.—E. t. 239, 

 /. 1.— Sow. Th. 1, p. 353, t. 70, /. 56, to 59.— ■Gray, Brack, p. 17, f. 3. 

 Rounded-ovate, ventricose, slightly diaphanous, very smooth, whitish 

 horn-coloured, devoid of mesial ridge or furrow, subequivalve ; outline 

 nearly straight ; upper valve dorsally rounded, recurved and slightly 

 acuminated ; perforation small, entire, rather oblique, with a thick- 

 ened margin ; cardinal area indistinct, rounded, with united indistinct 

 deltidia. Lower valve nearly circular, slightly truncated ventrally ; 

 loop small, only one-fourth the length of the shell, arched and vaulted 

 at the tip. Inner margin entire. Mediterranean. 2 - 



T. Uva. Brod. Z. P. 1833 ; Z. T. 1, t. 22, /. 2.— Sow. Th. 1, 

 p. 353, t. 70, f. 53, 4, 5. — Gray, Brack, p. 18. Oblong, gibbous, 

 smooth, pale, slightly diaphanous, devoid of mesial ridge or furrow ; 

 marginal line sloping from the apex, then somewhat flexuous. Upper 

 valve dorsally produced, its apex reflected and truncated ; perforation 

 large, entire, very oblique, with a thickened margin ; cardinal area 

 indistinct, rounded ; deltidia small, united, concave. Lower valve 

 ovate-oblong ; internal appendage formed of two rays setting off from 

 the hinge and expanded at the ends. Inner margin entire. Gulf 

 of Tehuantepec. The punctation of surface is coarser than in 

 Vitrea. 



1 The following more scientific division, by Dr. Gray, is much 

 preferable, yet is scarcely to be practised without injury to the 

 specimens. By the sequence of species, aided by the notes, it is 

 made available to our readers : — 



Terebratulina. Hinge-line decidedly curved ; margin even or only 

 slightly ivaved ; loop attached to the hinge-plate only. Includes Tere- 

 bratula, Terebratulina, Waldheimia. 



Magasina. Hinge-line not much, if at all, curved; smaller valve 

 with a longitudinal depression; loop attached to the septum in tke 

 middle of tke smaller valve. Includes Terebratella, Magas, Bou- 



CHARDIA, MEGERLIA, MORRISIA, KrAUSSIA. 



Argiopina. Transversely oblong or semicircular ; loop attached to 

 the surface of the valve. Contains Argiope only. 



2 This and the succeeding species (the latter with doubt) are the 

 only recent shells included by Gray in Terebratula proper : — 



Terebratula. Smooth, convex ; beak truncated and perforated ; 

 foramen circular ; deltidium of two pieces, frequently blended ; loop 

 very short, simple, attached by its crura to the hinge-plate. 



