200 PEOF, p. M. Duncan's kevision of the 



Genus Eolampas. 

 Archiacia. 

 Claviaster. 

 Asterostoma. 

 Pseudasterostoma. 

 Metaporhinus. 



Genual Eolampas, Buncan ^ Sladen, 1882, Foss. Echin. W. Sind 

 {Pal. Lid. ser. xiv.), P^- ii- P- 62, pi. xvii., aud p. 150, 

 pi. xxxi. ; imS,Ann.^Mag. Nat. Hist. ser. 6, vol. ii. p. 329. 



Syn. Peialaster, Cotteau, 1884; Pseudopygaulus, Coquand, 

 1862, genus undes., only figured. 



Test small, tumid, ovoid, subdepressed ; the greatest height 

 correspondiDg with the apical disk, and very excentric in front ; 

 the anterior slope rapid and precipitous, the posterior region sub- 

 rostrate near the extremity. 



Apical disik excentric in front, small ; basals four, penetrated 

 by genital ducts ; madreporite central. 



Ambulacra flush, small, short, petaloid, subequal; the odd an- 

 terior aborted. Poriferous zones of the other ambulacra subequal. 



Peristome transversely oval, subcentral or very slightly 

 excentric in front, with a perpendicular wall reaching upwards 

 into the body-cavity. No bourrelets. Phyllodes very slightly 

 developed. Buccal pores opening into the peristomial margin, 

 with a small granule-like prominence over each, standing at the 

 extreme edge of the peristomial ring. Periproct marginal, 

 transversely oval. Tuberculation small, homogeneous, in sunken 

 Bcrobicules ; intermediate space sub granular and confluent. 



The ambulacral rosette is small in relation to the size of the^ 

 test, and the ambulacral petaloid ends terminate remotely from 

 the margin of the test. The anterior ambulacrum has no double 

 pores, and the grooves wliich are in their place do not present a 

 single pore. 



The interradial areas are largely developed abactinally. There 

 is a faint groove in front of the sunken peristome. The periproct 

 varies in its size aud height in the posterior surface. 



Fossil. Eocene of Asia (Sind) ; N. Africa (Algiers) ; Europe ? 



Genus Aechiacia, Agassiz, 1847, Ann. d. Sci. Nat. vol. vii. 

 p. 101. D'Orhig. 1855, Pal. Franc.., Terr. Cret. vol. vi. p. 283, 

 pis. 909, 9L0. Besor, 1858, Synopsis, p. 324. Cotteau, 



