262 THE FOSSIL ECHINOIDEA 



taking the above measurement as nearly correct, the relative dimensions of length to 

 breadth and height are : — Length to breadth 1 : 0-96 ; length to height 1 : 0'43. 



With regard to this description given by d'Archiac and Haime, it is to be 

 observed that the posterior interradium and the antero-lateral are subequal at the half- 

 way point, and that the measurement on the type is accompanied by deformation of 

 the test. The position of the apical system is incorrectly given, being too far forward ; 

 the ends of the petals are exceedingly indistinct in the type, and the poriferous zones 

 are not equal. The bent condition of the petals at the apex is incomprehensible. The 

 poriferous zones are not broad. The tubercles are not close and small. 



In fact the types chosen by d'Archiac were not only injured but worn, and were 

 not full grown. 



The most perfect specimen of the species Echinolampas discoideus, d'Archiac, in 

 the collection from the Nari series, is not crushed, and is therefore normal in height. 



It has the specific characters, and it is to be noticed that the madreporite separates 

 the postero-lateral radials~(ocular plates), that the posterior poriferous zone of the 

 antero-lateral ambulacra is sinuous or slightly doubly curved, being moreover longer 

 than the anterior zone, and that these ambulacra do tend to close. The posterior 

 ambulacra arewidely open. 



There is an evident greater tumidity of the test behind the apex than over the 

 region of the anterior ambulacrum, where there is some flattening. 



The above-mentioned specimen measures 89 millim. in length, and is 83 millim. 

 in breadth. The height is 36 millim. The relative dimensions are : length to breadth 

 1 : 0-93 ; length to height 1 : 0-41. 



Locality. Nari series (Oligocene). Trak Hill, seventeen miles south of Bula Khan. 

 Survey-number G -3-7-. 



Illustrations of the Species in Plate XLI. 



Fig. 1. The abactinal view. 

 2. The side view. 



A second specimen, smaller than the preceding, is broader and higher relatively. 

 Length 78 millim., breadth 74 millim., and height 35 millim. Relative dimensions : — 

 length to breadth 1 : 0-94 ; length to height 1 : 0'46. 



5. EcHiNOLAMPAS DiscoiDEiTS, d'Archiac, var. a, Duncan & Sladen. Plate XLI, Figs. 3-5. 



A large specimen, 113 millim. long and 105 millim. broad, is 54 millim. high, and 

 its relative dimensions are nearly those of the specimen we consider our type of 

 Echinolampas discoideus. 



It presents a decided flattening of the front margin, which becomes very decided 

 in larger specimens, measuring 126 millim. long ; and the relative proportions are — 

 length to breadth 1 : 0-93, and length to height 1 : 0-42. 



Locality. Nari series (Oligocene). Northern end of Watwaro range, between 

 Trak and Damaj. Survey-number G -7-7-. Trak Hill, seventeen miles south of Biila 

 Khan. Survey-number G -if-. Hindi Hill, north of Trak. Survey-number G ^^^^. 



