18 THE TERTIAHY FOSSIL ECHINOIDEA 



C050 Af and C 050. From a canon in Nummulitic rock between Maniara-Fort hill 

 and Karray. 



Illustrations of the Species in Plate IV. 

 Fig. 1. A large specimen, side view: natural size. 



2. The same, abactinal view : natural size. 



3. The same, actinal view : natural size. 



2. Amblypygus pentagonalis, Duncan & Sladen. Plate IV, Figs. 4-11, 



The test is pentangular in marginal outline, especially in young forms ; it is 

 longer than broad and broader than high, broadest at the distal ends of the antero- 

 lateral ambulacra, tumid at the ambitus, curving boldly to the apex, which is rather 

 behind the centre, and more precipitously from it to the posterior edge. The profile 

 seen from the front is nearly hemispherical. The actinal surface is tumid ; the peri- 

 stome is oblique, deeply seated and large ; and the long, nearly elliptical periproct 

 is large, and reaches from the margin to three fourths of its length from the 

 peristome. 



Length of a test 85 millim., breadth 77 millim., height 53 millim. ; relative length 

 to breadth 1 : 0-9, length to height 1 : 0-62. 



A smaller specimen is 78 millim. long, 72 miUim. broad, and 45 millim. high ; 

 relative length to breadth 1 : 0-92, length to height 1 : 0-57. 



The ambulacra are slightly raised above the level of the interradia, and add to the 

 pentangular appearance ; they are widely open at the margin and become narrower 

 where the normal poriferous zone merges into the series of double pores. The 

 peristome is rather straight at its anterior edge, and rather angular posteriorly, 

 the indefinite apex of the triangle being at the entrance of the right posterior 

 ambulacrum (No. I.) into the peristome. 



Locality. The same as Amblypygus altus, in the Nummulitic series of Kachh. 

 Survey-numbers C 050, C 050 A t, C 050 A. 



Illustrations of the Species in Plate IV. 

 Fig. 4. The test, side view. 



5. Abactinal view of the test. 



6. The peristome and part of the periproct. 



7. Ornamentation of the margin: magnified. 



8. Ornamentation, abactinal : magnified. 



9. Part of an ambulacrum, poriferous and interporiferous zones : magnified. 



10. Termination of normal poriferous zone in the double series of pores, and 



part of an interporiferous zone. 



11. Apical system : magnified. 



This species difiers from Amblypygus altus in its shape, the projection of the 

 ambulacra, and in the more elliptical periproct and triangular peristome. The orna- 



