112 THE FOSSIL ECHINOIDEA 



rows of large granules are present throughout, with occasionally a trace (quite 

 microscopic) of the inner small series, the large granule occupying, however, nearly 

 the whole of the space between the pore and the median suture of the area. 

 Dimensions. The following are the measurements of three specimens : — 



a. h. e. 



millim. millim. millim. 



Height 28 25 25 



Breadth 40 34 37 



Localities. In the Khirthar series of strata : — i. Twenty-four miles west of Kotri 

 (entering the hills on the road to Biila Khan's Thana). Survey-number -^• 



ii. Dharan Pass, near Laki. Survey-number -^— . 



iii. Gagar hill, east side of the Siirjana range. Survey-number ^^. 



Illustrations of the Species in Plate XXI. 



Fig. 1. The test seen in profile : natural size. 



2. Actinal view of a part of the test : natural size. 



3. Plates of the interambulacral area : magnified. 



4. Ambulacral plates a little above the ambitus : magnified. 



5. Ambulacral plates from a larger specimen at the ambitus: magnified. 



6. Ideal section of an ambulacral area. 



7. A portion of a spine : magnified. 



8. A young specimen seen in profile : magnified. 



9. Ambulacral plates from the same : magnified. 



Genus POEOCIDAEIS, Besor, 1854. 



Test circular, depressed above and below, inflated at the ambitus. 



Ambulacral areas broad and straight. Poriferous zones broad, scarcely sunken, 

 with simple pairs of pores directly superposed. Pores wide apart, united by a con- 

 jugating furrow. Interporiferous areas broad, with horizontal series of miliary 

 granules. 



Interambulacral areas wide, with two vertical rows of primary tubercles. Primary 

 tubercles with small mamelons, perforate, deeply crenulate. Scrobicules more or less 

 transversely oval, with shallow grooves more or less defined radiating from the 

 periphery towards the centre along the flank of the tubercles, with or without pores or 

 depressions at the outer extremity of the grooves. Scrobicular ring with a tendency 

 to become confluent. 



Peristome small, decagonal. 



Spines flattened, with strongly serrated edges. 



This genus was established by Desor* for the reception of some isolated plates 

 with scrobicules of the form and dimensions of large Cidarids, but characterized by 



* Synop. Echin. foss. pp. 46, 47. 



