SUMMARY. 



181 



Family IX.— ECHINOLAMPIDiE, Wncjht (Vol. I, p. 389). 



Test thin, oval or subpentagonal ; upper surface depressed, convex, or conoidal ; 

 vertex usually excentric surface bearing small, often perforated, tubercles. Arabulacral 

 areas petaloid on upper surface, straight or slightly petaloid on lower. Oral opening 

 small and lobed. Jaws absent. Anal opening marginal, supra-marginal, or infra- 

 marginal, not in a sulcus. The Bchinolampidse range from the Oolitic to the existing 

 period. One British Oolitic genus (Pygurus) and six species. 



, Genus 21. — Pygurus, cC Orhigny (Vol. I, p. 391). 



Test thin, large, discoidal, subpentagonal ; upper surface slightly conical, under 

 surface concave and undulating, rostrated behind, sulcated in front. Tubercles small, 

 perforated, larger on under than upper surface. Ambulacral areas distinctly petaloid on 

 upper, subpetaloid on lower surface. Pores in a single series, until near the oral opening, 

 there becoming closely crowded in triple oblique ranks. Oral opening pentagonal and 

 excentric, strongly lobed. Jaws absent. Anal opening oval, infra-marginal, sometimes cor- 

 responding to, sometimes transverse to, the direction of the longest axis of the base of the 

 test. Apical disc small. Genus found in the Oolitic and Cretaceous strata. Six British 

 Oolitic species (Vol. I, pp. 392—405, 467). 



Order II.— ASTEROIDEA, WrigU (Vol. I, p. 4, Vol. II, pp. 1—22). 



Body stellate, depressed, provided with five or more hollow arms {rays) containing 

 (in the living state) prolongations of the viscera. Mouth {oral opening) always central on 

 the under side, and sometimes serving as an anal opening as well. Anal opening, when 

 present, subcentral on the upper side. Skeleton consisting of many solid calcareous 

 pieces, variable as to number, size, and position. Integument {perisome) coriaceous (in 

 the living state), and studded with calcareous spines of various forms, and also with 

 tubercles carrying a crown of short bristly spines {paxilla). Rays grooved and pierced 

 at the centre of the under surface with two or four sets of pores for the admission (in 

 the living state) of retractile tubular suckers, which pass between the edges of internal 

 ossicles and not through them. Upper surface of body marked by one or more madre- 

 poriform tubercles near the angle between two rays. Eyes (in the living state) generally 

 present at the extremity of the rays. No dental apparatus. Small, pincers-like bodies 

 supported on slender flexible stems {pediceUarice), on the integument surrounding the 

 mouth and bases of spines. Movement of the body performed by the suckers and spines. 



