CRETACEOUS ECHINODERMATA. 335 
Ksq. at Balcombe pit, Amberley, and is a distinguished ornament in Mr. Dixon’s 
cabinet. 
Goniaster (Astrogonium) angustatus. (Tab. XXIII. fig. 10.) R.3. 
Body deeply lunated at the sides, and having the angles much produced. 
Marginal ossicles of each row about 24 on a side, the 8 central ones nearly 
equal ; steep-sided and thick with a short superior surface, tumid and punctate ; 
their exposed side smooth. Those of the arms differ from the corresponding 
plates in G. Coombii in having more rounded outer sides and less regularly 
tumid summits. 
Upper chalk, Kent. Two specimens and a fragment in Mr. Bowerbank’s col- 
lection, also from Sussex ; and a fine specimen in the British Museum. 
Sreviaster, Gray (including Compronia, Hosa and Diacona, Gray). 
The star-fishes of this genus are five-rayed, and more or less pentagonally 
stellate. The upper disc is slightly convex and covered with closely-set penta- 
gonal plates, which, when the animal is alive, bear closely-set, very small 
granules, giving them a frosted appearance. ‘The interstices of the plates are 
porous. In some species, small conical spines are borne on the upper disc at 
distant intervals. The madreporiform tubercie is very distinct, and near it is 
the vent. The sides are margined by two rows of large plates, those of the 
upper and lower row being nearly equal. In some species both upper and lower 
marginal plates bear one or more spines, in others the lower only. In rubbed 
or dead specimens these spines disappear. Linear sessile pedicellariz are 
seen on both marginal and body plates in some living species, but are entirely 
absent in others. The rays are terminated by an eye-plate, which is usually larger 
than the lateral eye-plates. The avenues are bordered by comb-like series of 
spines, backed by a row of stronger ones. The surface of the plates, both of the 
margin and disc, is more or less frosted, but is not covered by minute granules. 
The living species are tropical or Australian, and fossil ones from the lower 
greensand closely approach them in structure. 
Stellaster Comptoni, Gray. (Tab. XXII. fig. 8.) R. 2. 
Disc broadly pentagonal, with moderately long produced arms. Marginal plates 
narrowly oblong, widening on the arms: those bordering the disc superiorly 
presenting a great part of their surface. Many of them marked by oblique grooves 
2x2 
