10 FAUNA OF BALUCHISrlN. 



be made in nearly every individual. After a certain height has been attained the 

 corallvim increases quicljer in height than in breadth: young specimens have 

 therefore a triangular cross section in the direction of the larger diameter, while the 

 section of a full grown specimen seems to be composed of two parts, a more rectan- 

 gular upper and triangular basal portion. 



The calyx is elliptical, and, as' will be seen from the above figures, the large 

 diameter is more than double the length of the short diameter. The corallum has 

 therefore a markedly compressed shape. Tossula narrow, rather shallow and 

 elongated. No columella. There are six complete cycles of septa, of which those 

 of the first and second cycle are nearly equal in size, but much larger than the. 

 others. The septa are very thin, straight and closely set, their upper edge being 

 granulated, Inferior part of the visceral chamber completely filled out by dissepi- 

 ments. The surface is covered with straight, continuous, very delicate granular 

 costae of equal thickness at the upper margin of the calyx. Epitheca rudimentary, in 

 narrow bands, marking periods of stopping in the continuous growth of the corallum. 

 Locality and stratigraphical position. — Mazar Drik. 



Bemarks. — The peculiar shape of the corallum distinguishes this species easily 

 from the other forms of this genus. 



One of the specimens fig. 10a exhibits a curious phenomenon, which is rather 

 difficult to explain in a specimen of 42 mm. in length. The basal portion of the 

 corallum is broken off, and imbedded in the visceral chamber there is a complete 

 specimen of a ModiOla, resting in an oblique position, both valves still together, 

 with the beaks turned downwards, of not less than 18 mm. in length, the breadth 

 of the corallum being about 24 mm. From the foregoing remarks regarding the 

 lower part of the visceral chamber which is completely filled up by dissepiments, it 

 is impossible that the shell could have been imbedded in its present place as it is 

 after the death of the animal, and it is equally impossible that the shell represents 

 a species of Lithophagm which has bored into the corallum, because there 

 is no sign of a hole in the wall of the corallum through which the shell could find its 

 way into the visceral chamber. As there is also not the slightest indication of a bore 

 hole in the calyx or anywhere above the place which the shell occupies, it seems to 

 me unquestionable that the shell must have got into its present position during the 

 life of the coral which eventually grew over it and imbedded it in the endotheca. 

 It is difficult to say how the Modiola originally acquired its present position ; 

 it is not impossible that it led a parasitical life inside the visceral chamber till it 

 was eventually imbedded in the, endotheca and died. 



Family : TRAMNA&TR^IBJU. 



Genus : CTOLOLITES, Lamarck.. 



Ctclolites meducotti, spec. nov. PI. I, fiigi 11-lld, 12-12J. 



The corallum is circular in outline, sometimes rather ovate. The base is flat, 

 even a little concave ; the epitheca is thin, marked with numerous concentric 



