SUMMARY. 
187 
Range of genus from the Trias to existing period. Three British Liassic and Oolitic 
species (Vol. II, pp. 150, 151, 160, 161). 
Genus 32. — Acroura, Agassiz (Vol. II, p. 152). 
Disc small, arms long and slender, supporting on their lateral borders small scales. 
Range of genus from the Trias to Lias. One British Liassic species (Vol. II, p. 153). 
Germs 33. — Amphiura, #or^(?s (Vol. II, p. 158). 
Disc small, orbicular ; upper surface covered with smooth small scales, the six central 
plates forming a rosette. Arms long, covered with scales, and exhibiting on the margins 
simple lanceolate spines. Range of genus from the Oolitic strata to existing period. 
One British Oolitic species (Vol. II, p. 158). 
Section C. — Tier genital fissures on each interbrachial space. Disc memhranous and 
naked. 
The section ranging from the Silurian strata to the existing period is represented by 
one British Oolitic genus (Ophiurella) and two species. 
Genus 34. — Ophiurella, Jgassiz (Vol. II, p. 154). 
Disc small, membranous. Arms long and slender, bearing on the lateral margins 
elongated fihform spines. Genus found in the Oolitic strata. Two Britisli Oolitic species 
(Vol. I, pp. 154, 156). 
