SHALLOW-WATER STARFISHES 359 



It varies much in appearance, according to age, and has many local 

 or casual varieties. Whether all the forms referred to it by Leipoldt 

 and others really belong together seems to me somewhat uncertain. 



I have studied a series of young and old from Eden Harbor, Pata- 

 gonia, sent by the Museum of Comparative Zoology. These show 

 wide variations, especially in the character of the dorsal rows of 

 spines and the number of spines on each plate. The number increases 

 rapidly with age, so that the larger specimens (radius, 175 mm.) 

 have very numerous, crowded, transverse groups of spines and pedi- 

 cellariae, the median and some of the others forming thick, wide, longi- 

 tudinal rows. The madreporic plate is surrounded by a circle of small 

 special spines, increasing in number with the age, from six or seven 

 up to twenty or more. 



The major pedicellarise are large and stout. Some are obtusely 

 lanceolate or ovate, others are blunt and unguiculate, with few teeth. 

 They are abundant on the edge of the grooves, where many have long, 

 slender pedicels, and between the ventral and lateral spines, and on 

 the dorsal papular areas, where they are often stouter than the adja- 

 cent spines. Minor pedicellariae are abundant on the dorsal dermis, 

 crowded, especially over the transverse ossicles and between the 

 spines. 



The larger specimens may have six to eight interactinal spines in a 

 transverse row, arising, apparently, from three, to five, rows of plates. 

 Young specimens, with the greater radius 50 mm., have only two 

 rows of interactinal plates, each with one or two spines, and the 

 spines on both marginal rows stand partly singly, partly two to a 

 plate ; there are but three dorsal rows, and the spines in these stand 

 partly in pairs, partly singly. 



This species occurs on both coasts of Patagonia and Fuegia, from 

 low tide apparently to 348 fathoms. 



COSMASTERIAS TOMIDATA (Sladen). 

 Cosmasterias tomidata Sladen, 1889, p. 576. 



This has more regular rows of small, clustered dorsal spines, and 

 very numerous dermal minor pedicellariae, larger than usual. The 

 major pedicellariae are numerous, large and stout, often much larger 

 than the spines ; mostly strongly felipedal. 



Gulf of Penas, 45 fathoms, Sladen ; Porto Lagunas, etc., 50 to 80 

 meters, Leipoldt ; off Argentina, S. lat. 44° 52', 55 fathoms, coll. Mus. 

 Comp. Zoology. 



