History of British animals - University of Guam Marine Laboratory

480 RADIATA. PLEUROCYSTI. Spatangus.Gen. IV. SPATANGUS.— Avenues of pores circumscribed.A grooveor band extends from the mouth, which is transverselylunate, to the four orifices of the oviducts in thevertex. Anus in a compression in the margin, with a circumscribedspace immediately underneath.a. A suhquadrangular space on the vertex, containing the orificesof the oviducts, inclosed by a narrow band. The pairs ofpores in the avenues not connected by lines. Compressionat the vent vertical.Heads; Sea-eggs.— A deep groove16. S. cordatus.— Mermaidson the margin between the mouth and vertex.Echinus spatagus, Merret, p. 192., Depressed cordate sea-egg. Bor.Corn. p. 278. tab. xxviii. f. 28.— E. c. Penn. Brit. Zool. iv. p.69.t. xxxiv. f. 75 Spatagus flavescens, Mutter, Zool. Dan. iii.p. 17.tab. xci. f. 1-4 S. pusillus, Leske, ap. Klun. p. 230. t. xxiv. c, d, e.tab. xxxviii. 5.— Common in all the sandy bays.Length about two inches ;vertex hollowed ;oviducts in pairs, diverging,with an intermediate punctured space ; vent vertically ovate ;the inclosedspaces, beneath, rhomboidal, with two pores in the lateral angles; primaryspines few, on rough tubercles ; spaces between the pairs ot pores in theavenues smooth.7. S. ovatus.— Groove between the mouth and vertex obsolete.Flem. Wern. Mem. v. 287. t. 6., lower figure. Leske ap. Kl. p. 252.tab. xlix. f. 12, 13 Scottish coast, rare.Diameter an inch and a quarter, purple ;vertex nearly even ; oviductsapproximate, with the punctured space behind, and the spines covering thisplace produced vent ; transversely ovate, the inclosed space beneath cordiform,with single lateral pores ; primary spines, supported on tubercles, witha central ligament, and surrounded by a moniliform ring the ; spaces betweenthe pairs of pores in the avenues rough.This species differs so much from the preceding in so many characters, asto leave no room to doubt its claim to rank as a distinct species. Doubts,however, may be entertained as to the propriety of the synonym prefixed.This species is more globular than expressed in Leske's figure, and the linefrom the oviducts to the mouth, instead of being carinate, is flat- A singlespecimen of this species occurred to me in 1809 in Zetland. In 1825, DrColdstream found another on Leith sands.b. Destitute of a suhquadrangidar space on the vertex. Thepairs of pores in the avenues connected by transverse lines.Compression at the vent oblique.— 8. S. purpureus. Vertex sloping to the margin.Mutter, Zool. Dan. i. p. 5. tab. vi. 1-5. copied by Leske, tab. xliii. f. 3-5.with a good description Echinus lacunosus, Pcnn. Br. Zool. iv. p. 69.tab. xxxv. f. 76 On the English coast, rare—Frith of Forth, common.3