SHALLOW-WATER STARFISHES 353 



species have been described that closely resemble that genus, and may 

 possibly belong to it. 



On the other hand, there are found in the Patagonian fauna, and 

 farther south, numerous species and varieties of monacanthid star- 

 fishes, most of which are known to carry their eggs and young (pado- 

 phoric) and to have, in those species dissected, ventral genital pores. 



These have been referred to the genera Anasterias Perrier, 1875 ; 

 Cahasterias Perrier, 1875; Sporasterias Perrier, 1894; P&dasterias 

 Verrill, gen. nov. 



Another group of padophoric species includes several diplacanthid 

 species, belonging to the genera Podasterias Perrier and Granaster 

 Perrier. None of these are known in the northern hemisphere. 



The genera Meyenaster Verrill, May, 1913 (monacanthid), and 

 Cosmasterias Sladen, 1889 (diplacanthid), also characteristic of this 

 region, have not yet been observed to carry their young. 



The most common and abundant littoral and shallow-water star- 

 fishes of both coasts of Terra del Fuego and Magellan Strait belong 

 to a monacanthid generic group with a reticulated dorsal skeleton, 

 for which Sporasterias Perrier, 1894, seems to be the earliest tenable 

 name, with S. rugispina (Stimpson, 1862, as Asterias) for its type. 

 This group, which we may also designate as the rugispina 1 or ant- 

 arctica group, has commonly been called Anasterias Perrier. The 

 latter was originally based solely on A. minuta Perrier, a small, doubt- 

 less very young starfish, with a thick dermis, rudimentary dorsal 

 skeleton, and few dorsal spines, and thus quite unlike the group 

 that we call Sporasterias. (See Anasterias, below, p. 354.) 



F. Leipoldt (op. cit., 1895, p. 563) proposed to unite nearly all the 

 then known monacanthid starfishes of the Antarctic seas into one 

 comprehensive and exceedingly variable species. This would be a 

 very convenient arrangement, perhaps, if it would only prove true. 

 No doubt, however, many of the nominal species of this group are 

 synonymous ; and the species are certainly variable, as are all others 

 that carry and incubate their eggs and young. 



Among the forms united by Leipoldt, under the name Asterias 

 rugispina, the following belong apparently to Sporasterias, having a 

 reticulated dorsal skeleton and many spines, not submerged in a thick 

 dermis: Sporasterias antarctica (Liitken, 1856) ',S. rugispina (Stimp- 

 son, 1862, as Asterias) ; S. varia (Phil., 1870) ; S. rupicola (Verrill, 



1876, as Asterias) ; S. perrieri (Smith, 1876, six-rayed, as Asterias, 

 non A. perrieri Studer, 1884) ; 5. cunninghami (Perrier, 1875, as 

 Asterias) ; S. spirabilis (Bell, 1881, as Asterias) ; 5\ hyadesi (Per- 



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