76 FAUNA OF BALUCHISTAN. 



saddle does not show in any of the related species such a large and deep secondary 

 lobe as in Indooeras haluohistanensis. Tissotia ewaldi shows a suture line which 

 in this respect closely resembles that of Indoceras balucMstanensis ; but quite- 

 apart from the fact that Tissotia ewaldi has a smaller number of auxiliary lobes, 

 the inner branch of the external saddle is much higher and broader than the outer 

 one, while in Indoceras balucMstanensis the two branches are of nearly the same 

 strength and height, although the inner one is perhaps slightly higher. 



So far as I can judge, Indoceras balucMstanensis exhibits the greatest differ- 

 entiation of the external saddle of all the specimens belonging to this group. 



Genus : SPHENODISCUS, Meet. 

 Sphenodiscus acutodoksatos, spec. nov. PI. XXI, fig. 3-3A, 



The discoid shell consists of very high whorls, much compressed laterally, whicb 

 overlap each other so fully that only a narrow and shallow umbilicus remains. 

 The sides are apparently perfectly flat and slope slightly towards- the siphonal side j 

 the latter is very narrow and bears a sharp keel up to the end of the body chamber. 

 The body chamber occupies about three quarters of a volution, and, apparently, it 

 suddenly widens out so much towards the aperture that its thickness near the latter- 

 is quite double of what it is just above the last septum. 



Only one branch of the siphonal lobe is visible, but from that we may conclude 

 that it was rather narrow and not very deep ;, the fi.rst lateral lobe is narrow, but 

 rather deep, and ends in short pointed denticulations ;, the second lateral is of only 

 about half the length of the former and indistinctly denticulated. There are at 

 least five short narrow auxiliary lobes, of which the two or three fij^st ones are 

 denticulated. 



The external saddle is very broad and divided by two secondary saddles intc 

 three phylloid branches. 



The first two, which are rather narrow, rise slightly, diverging from a common 

 basis ; the third branch, separated from the others by a deep secondary lobe, is rather 

 broad and rounded ;, the other saddles are of the same type, but shorter and always- 

 much broader than the lobes. 



Locality and stratigraphical position, — Des valley near Khattan ; second' 

 specimen, Mazdr Drik. 



Bemarks. — Only two of this species have come under examination, neither of 

 which are particularly well preserved. The better preserved specimen, given by 

 Mr. E. A. Townsend to Mr. Oldham, is much affected by weathering, but it stili 



