128 CEETACEOUS PELECYPODA 



sinus is in the fossil form smaller than in any recent species of that group which I 

 have examined. 



Locnlily. — Odium, in a brownish earthy limestone. 



Formation. — Ootatoor group. 



6. Tellixa [Arcopagia] discites, StoUczka, PI. IV, Fig. 15. 



Tell, testa suhdiscoidea, parmila, solidula, concentrice minute striata, ceqiiilaterali, 

 antice ac postice rotundata, marginibiis siiperioribns ad apicem anguliim 11G° 

 formantihus ; dentibus cardinalibns in vulva dextra distinctis. 



A small species, but very distinct from any of the other cretaceous TelUnce ; 

 the disciform almost quite equilateral shape and the strong development of the 

 lateral teeth entirely agrees with the sub-genus Arcopagia. It is not very prol)able 

 that the specimen figured is a very young shell, for it is of rather a solid structure. 

 The upper sloping lateral margins form an angle of about 116 degrees, the anterior 

 and posterior ends being both rounded. 



iom/zY//.— Moraviatoor, in a dark-brown earthy limestone. 



Formation. — Ootatoor group. 



7. Tellina [Tellinides] adpressa, StoUchza, PL IV, Fig. 14. 



Toll, testa ovato-elonr/ata, 2)erte?mi, valde compressa, fere <2quilateraU, ad 

 iitramque extrcmitatem late rotundata ; umhonibus ])('tilidiim prominidis, marginibus 

 .siiperioribus parmnpev descendentibus ; superficie minntissime concentrice striata. 

 Cardo in valva dextra dentibus duobus cardinalibns, anteriore bijido instruct us j 

 dente lateraU antico distincto, postico fere obsoleto. Altiti(,do : longit. ^^0' 68. 



This is a remarkably compressed and very thin shell ; it is almost equilateral, 

 equally broadly rounded at both ends, and there is no trace of a posterior ridge 

 observable; the upper margins are very little descending, the beaks being 

 minute ; the surface is covered with very fine and numerous concentric striae. The 

 liiuge of the right valve is composed of two cardinal teeth, of which the anterior 

 one is bifid ; the anterior lateral is distinct, but the posterior almost obsolete (it is 

 too strongly represented in fig. 14i). The proportion of height to length is 0-68. 



Tar. — altitudiiie testa; : longit. 0-60, pi. xvi, fig. 25 ; testa margine inferiori 

 ad medium parumper insinuato instructa. 



This form appears to be only a variety of the former, at least the only speci- 

 men found at present does not allow of any better conclusion. The shell is slightly 

 more elongated, and the upper margin slopes under an angle of about 112 degrees ; 

 structure and striation of the surface is equally fine and quite similar to the former. 

 Tliere is a very shallow conspicuous depression running from the beak to the inferior 

 margin, and this very much resembles some Psammotcea, and is the principal 

 (diaracter which gives the shell a somewhat different aspect from the one above 



