SHALLOW-WATER STARFISHES 243 



i&to; Synopsis, p. 4, 1866. Verrill, Proc. Boston Soc. Nat. Hist, x, 

 p. 345, 1866 (Solaster and Crossaster first separated). Agassiz, North 

 American Starfishes, pp. lll, 112, 1887 (structure). Perrier, Exped. 

 Trav. et Talism., p. 154, 1894. Sladen, op. cit, p. 450, 189. 



Crossaster (pars) Muller and Troschel, Monatsb. Preuss. Akad. Wiss., 

 Berlin, April, 1840, p. 103. 



Solaster (pars) Viguier, Nouv. Arch. Zool. Exper., vii, p. 138, 1878 (struc- 

 ture). Bell, Catal. Brit. Echinod., p. 88, 1892. 



Solaster (pars) Danielssen and Koren, Norw. N. Atlantic Exp., Asteroidea, 

 pp. 42, 52, S3, 1884 (structure). Fisher, op. cit., 191 1&, 306. 



Disk rather broad. Rays seven to twelve, variable in each species. 

 Dorsal ossicles small, mostly subcruciform or slightly four-lobecJ, 

 sometimes stellate, usually reticulated, or in quincunx, on the disk 

 and proximal part of the rays, but closely imbricated near ends of the 

 rays, and often arranged in regular quincunx order ; sometimes 

 united by smaller ossicles. They are convex or slightly mammillate, 

 with a central boss, and bear a stellate or fasciculate cluster of 

 slender spinules, webbed together, and usually enclosing one or 

 several central spinules, connected by the web, forming pseudo- 

 paxillaj. The outer circle of webbed spinules often forms a funnel- 

 shaped structure in life, or when well preserved ; but the spinules 

 are movable, and in dry specimens they are usually mostly collapsed 

 or tipped over, thus forming irregfular groups or pencils or small 

 spinules, from five to twenty or more in a group. 



The superomarginal plates are small and close to the larger infero- 

 marginals, usually alternating. They are usually hardly distinguish- 

 able from the dorsal pseudopaxillae, except near the ends of the rays, 

 but they extend regularly to the apical plate. 



Inferomarginals much larger and more elevated, transversely 

 oblong, forming a rather conspicuous row. They bear a large num- 

 ber of paxilliform spinules in two or more transverse rows. Adam- 

 bulacral plates usually have two to four shorter groove-spines, 

 webbed together, and an actinal transverse row of four to nine or 

 more longer spines, also webbed. 



The interradial actinal areas are small, but distinct, and bear 

 pseudopaxillae, much like the dorsal ones. 



Papula; are numerous on the dorsal surface, but stand singly or in 

 small groups. A single row of peractinal pseudopaxilla; usually 

 extends along the proximal part of the rays, to about the middle. 



The eggs and young are carried attached to the oral region in 

 clusters in 5". endeca and other species. 



The structure of the skeleton has been very fully described and 

 beautifully illustrated by Agassiz in the work cited above. 



