94 



somewhat circular, flattened ; internal appendage consisting of a 

 single prominent gnomon near the fiont ; margin of the valves entire. 

 Found by Mr. Cuming attached to corals at Calapan, isle of 

 Mindoro ; also from the island of Cocos, Lieut. Swainson ; in the 

 late G. Humphrey's coUection. 



Terebratula cognata, Chemn. Ter. testd subtrapezoidali, antice 

 rotundatd, pallescente, nonnunguam rubente ; valvis in<equalihus, 

 radiatim obsolete striatis, versus marginėm obliteratis ; lined mar- 

 ginali lateraliter anticegue flexuosd ; valvd dorsali conveid, lird 

 mediand inconspicud ; apice subacuminato reflexo ; foramine magno, 

 haud integro ; ared cardmali a7igustd, deltidiis jmrvis, trigonali- 

 bus ; valvd ventrali planulatd, margine postico rectiusculo ; sulco 

 mediano subperspicuo ; ossiculo interno ramulos duos centrales, 

 divergentes, adapices expansos sistente ; margine interno valvarum 

 denticulato. 

 Shell nearly trapezoidal, rounded in front, of a pale colour, some- 

 times reddish ; valves uneąual, obsoletely radiately striated, the strise 

 entirely obliterated near the margin ; marginai line flexuous in front 

 ahd on the sides ; dorsal valve eonvex, \vith an inconspicuous centrai 

 ridge, its apex somewhat acuralnated, reflected, with a large incom- 

 plete perforation ; cardinal area narrow, \vith small triangular del- 

 tidia; ventral valve flattened, its posterior margin nearly straight, 

 ■with a scarcely evident centrai furrow ; internal appendages con- 

 sisting of two little centrai diverging branches, exparided at their 

 apices ; margin of the valves denticulated %vithin. 



There are two varieties in colour, from South Africa, according to 

 the late G. Humphrey. 



Terebratula transversa. Ter. testd transversim subovatd, tenui, 

 rudi, glabrd, pallescente ; lined marginali subflexuosd, antice sub- 

 sinuatd ; foramine maximo, incompleto ; ared cardinali magnd, 

 planatd ; deltidiis parvis, longe discretis ; carind dorsali incon- 

 spicud, rotuiidatd; valvd ventrali transversim oblongd, antice 

 rotundatd, postice in angulo obtusissiino desinente ,■ sulco mediano 

 subinconspicuo, rotundato ; margine valvarum integro. 

 Shell transversely subovate, thin, rugose, smooth, of a pale colour ; 

 marginai line somewhat flexuous, slightly sinuated in front ; dorsal 

 valve of a somewhat tetragonal ovate form, very obtusely angular 

 behind and reflected ; perforation very large, incomplete ; cardinal 

 area large and flattened ; deltidia small, very distant ; mesial ridge 

 rounded, indistinct ; ventral valve transversely oblong, rounded in 

 front, and finishing in a very obtuse angle behind ; mesial groove 

 rounded ; indistinct margin of the valves entire. 



In Mr. Norris's collection and in that of Mr. Janelle. 



Terebratula rubella, So\v. Ter. testd subovatd, postice sub- 

 acmninatd, snbgibbd, antice subsinuatd, rubrd ; valvis inagualibus, 

 glabris ; lined marginali rectiusculd, antice subsinuatd; valvd 

 dorsali postice subacuminatd, reflexd, carind mediand nulld, sulco 

 mediano obsoletissimo, foramine parvo ; ared cardinali angustd, ad 



