PELECZPODA. 45 



on the anterior declivity of the greatfist median convexity of the valves, but this 

 species is readily distinguishable by its broad, expanded, posterior side, and the striae 

 of growth, which bear exactly the opposite character to those of Modiola vishnu by 

 being stronger on the posterior, and finer on the anterior side. 



3. Order: HETERODONTA. 

 Suborder; Conch ace a.. 



A. INTEGRIPALLIATA. 



I. Family: ASTARTIDjE. 



Genus : CARDITA, Brag. 



Cakdita (Venericaedia) bbaumonti, d'Archiac and Haime, var. Baltjchis- 

 TANENSls, Ifoetling. PL XII. fig, 2, 2A. 



1863. Car/Hita beanmpnti, d'Archiac and Haipae, Description des Anim, foss. du Gioupe Numm. de I'lcde, 

 p. 253, pi. XXI, fig. 14, a, b. 



The bad state of preservation of all the specimens which have come under 

 examination does not permit description of the general shape of the shell. But one 

 fact seems to be certain, that the Baluchistan form has attained a larger size than 

 the Sind type ; there is a fragment of a specimen which was certainly not less 

 than 47 mm. in height, while the largest specimen from Sind, which has come 

 under examing,tion, measures not more than 33 mm- in height. Both valveg are 

 highly inflated, the beaks are tumid, and strongly rolled inwards. The ornament- 

 ation consists of strong and broad radiating ribs, of which those on the posterior 

 side are much thinner than those on the anterior and central part of the surface. 

 On the anterior side the ribs aye strongly curved, but they beconje more and more 

 straight in posterior direction. On the anterior and central part of the surface 

 the ribs are broad and flat, and carry three keels, two sharp ones on either side 

 and a broad and rounded one in the middle. The interstices are about one-half to 

 one-third of the breadth of the ribs, deep and concave. Numerous closely set strige 

 of growth produce a line of foliaceous granulation on the ribs, particularly on the 

 median ridge. 



Locality and stratigraphical position. — Maz4r Ddk, horizon 8. 



Hemarks. -r-lt is greatly to be regretted that none of the specimens collected in 

 Baluchistan is complete enough to give an idea of the general shape of the shell, as 

 I suspect that there must exist some constant distinctive features between the types 

 from Baluchistan and Sind, which cannot be overlooked. 



As already stated, the Baluchistan types attain a larger size than the Sind 

 ones. Full grown specimens of the latter are of very uniform size, which, as 

 p,lready stated, does not exceed 33 mm. in height. The Baluchistan specimens on 



