OF WESTERN SIND. 327 



5. Clype ASTER DEPEESSUS, Sowerhy. 



This species was described by Sowerby in Grant, Trans. Geol. Soc. ser. 2, vol. v. 

 pt, 2, and we noticed it in the description of ' The Fossil Echinoidea of Kachh " in 

 1883, p. 58. It is a common Miocene form in Kachh, and there is a well-marked 

 specimen in the Gaj deposits. We do not figure the form, as the drawing on Plate X, 

 Figs. 5-9, in the Kachh Echinoidea will suflice. 



Locality. Gaj series or Miocene of Sind : About three miles south-east of Tong. 

 Survey-number G -g^. 



Family SCUTELLIDM 



The test is reduced to its extreme flatness among the Clypeastroids ; the outline 

 is more or less circular and is frequently cut at the margin or perforated, so as to form 

 ambulacral cuts or lunules. The ambulacral furrows on the actinal side are more or 

 less branching and anastomose, spreading over to the interradial spaces. Connection 

 between the upper and lower floors of the test is by radiating fan-shaped partitions, 

 coming from single points. The tubercles of the upper and lower surfaces of the test 

 as well as the spines which they carry differ much in size. The rotulse of the dental 

 apparatus are absent and the auricles are low. The teeth are more or less horizontal. 



Genus ECHINODISCUS, Breyn., amended A. Agassiz, 1872. 



This genus was established by Breynius in 1732, but A. Agassiz so modified the 

 scope of it in his ' Revision ' that it is no longer correct to add the name of the original 

 founder to a description which differs considerably from that which he gave. As we 

 have already stated in our Monograph of the Tertiary Echinoidea of Kachh and 

 Kattywar (' Palseontologia Indica '), the genus as now defined contains the genera 

 Lolophora and Anijahiope. It is one of the family of the Scutellidse, Agassiz, amended 

 by his son in the revision of the genera, 1872-74. 



The following are the essential points in the diagnosis of the genus according to 

 A. Agassiz (Revision, &c. p. 531): — 



The test is more depressed than in the other Scutellidse and is thin ; anterior edge 

 rounded, posterior truncated. There are two lunules, or cuts, corresponding to the 

 posterior ambulacra. Ambulacral petals small and well limited. Four genital pores. 

 Lower surface flat, and the furrows ramify but little towards the exterior edge. Anus 

 nearer the posterior edge than to the peristome. The greater part of the test is 

 occupied by a calcareous network rising into pillars for more than half the distance 

 between the edge and the peristome, internally leaving the central part more or less 

 covered by a delicate tracery of limestone cells into which the appendages of the 

 alimentary canal are received. No pillars or partitions separate the buccal cavity from 

 the alimentary canal. 



