84 ASTEEOIDEA. 



on each Bide of the median radial line. The disk is large and 

 extraordinarily flat. 



1. Palmipes placenta. 



Asterias placenta, Penn. Brit. Zool. iv. (1777) p. 53, pi. xxxi. 

 fig. 59 A. 



Asterias membranacea, Retz. Vet.-Akad. Nya Hdlg. iv. (1783) p. 238 ; 

 L. ed. Gmel. Syst. Nat. (1788) p. 3164 ; Rets. Diss. Spec. Ast. 

 (1805) p. 12; Lamh. An. s. Vert. ii. (1816) p. 558; Belle Ch. 

 Descr. An. Invert. Sic. cit. iv. (1841) p. 56, v. (1841) p. 122, pi. 127. 

 figs. 8-10, 12, 14, 15. 



Asterias cartilaginea, Flem. Brit. An. (1828) p. 485. 



Anseropoda inembranacea, Nardo, Isis, 1834, col. 716. 



Palmipes membranaceus, Ay. Mem. Soc. Neuchdt. i. (1836) p. 192 ; 

 Forbes. Mem. Wern. Soc. vii. (1839) p. 119, pi. iii. fig. 3 ; Thomp- 

 son, Nat. Hist. Irel. iv. (1856) p. 440 ; Duj. §■ Hup. Fchin. (1862) 

 p. 373 ; Fischer, Act. Linn. Soc. Bord. xxvii. (1872) p. 367 ; Perrier, 

 Arch. Zool. exper. v. (1876) p. 210 ; Viguier, Arch. Zool. exper. 

 vii. (1878) p. 212. pi. xiv. figs. 1-5; Ludw. Mitth, zool. Stat. Neap. 

 i. (1879) p. 541 ; Scott, Proc. R. Phys. Soc. Edin. 1890-91 (1892) 

 p. 82. 



Asteriscus palmipes, M. Tr. Syst. Ast. (1842) p. 39 ; Heller, Zooph. 

 u. Ech. Adriat. Meer. (1868) p. 53 ; Schmidt/ein, Mitth. zool. Stat. 

 Neap. i. (1878) p. 126. 



Palmipes placenta, Norm. Ann. Sf May. xv. (1865) p. 120 ; Parjitt, 

 Trans. Devon Assoc, v. (1872) p. 359. 



2 E = 3 r (nearly). 



A perfectly flat species, liable to a good deal of distortion in 

 drying. Of the form of a pentagon with curved or angulated sides ; 

 sometimes almost round. Ambulacra rather wide, fringed by a row 

 of spines, ordinarily set by fives on each ossicle ; outside these there 

 is a transverse row of three or four spines. The ossicles on the 

 ventral surface carry from ten to two or three spines according as 

 they are near to or far from the mouth ; these spines are much 

 longer than the much finer and more glossy spinelets, which are 

 more numerously represented on the ossicles of the dorsal surface. 

 The small, rather obscure madreporite is quite close to the centre 

 of the disk. 



Colour red in the centre and at the edges, above and below ; 

 red along the rays above ; elsewhere white. Gradually fades when 

 dead ; the red colour quite lost in spirit-specimens. 



E. r. 



93 63-5 



72-5 51 



70 42-5 



54 32 



40 26 



36 29 



27 21 



The five Rs and rs are frequently respectively different in one and 

 the same specimen. 



