SHALLOW- WATER STARFISHES 361 



back and on the sides, which enclose rudimentary or nearly abortive 

 spinules. The skeleton is almost entirely abortive ; marginal plates 

 are not present, unless as rudiments. 

 The type is from the Antarctic Ocean. 



Genus Podasterias Perrier, 1896. 



Type, P. lutkeni Perrier. 

 Diplasterias (pars) PERRIER, 1891, p. K, 77. Ludwig, Voy. Belgica, 1903. 



This genus is here extended to include several paedophoric dipla- 

 canthid starfishes having a reticulated dorsal skeleton, not concealed 

 by a thick dermis, and usually two or more rows of interactinal plates 

 and spines. Thus they have a general resemblance to typical Asterias, 

 like A. rubens. As some of the species are known to carry their 

 young, the genital pores are presumed to be ventral, but I do not 

 know that any species has been dissected with reference to this. 

 Among the species that appear to belong here are the following : 



P. lutkeni (Perrier, 1891, p. K, 81, as Diplasterias) . 



Fuegian and Falkland Is., 95 to 220 meters. 



Podasterias steineni (Studer, 1885, pi. i, figs. 40, b, as Asterias). Diplasterias 

 steineni Perrier, 1891, p. K, 84. 



South of Cape Horn, 99 meters (Perrier). 

 P. loveni (Perrier, 1891, p. K, 80, as Diplasterias). 



S. lat. 52 44' 31", 320 meters. 

 P. spinosa (Perrier, 1891, p. K, 82, as Diplasterias). 



S. lat. 47 29', depth not recorded. 

 P. meridionalis (Perrier, 1875, P- 34> as Asterias). 



Antarctic Expedition. 



Some of the several species, from the same region, described by 

 Bell in 1881, probably also belong here, but the skeletal structure was 

 not described. 



The first two species have been found carrying their young. 



The name Diplasterias Perrier is not adopted for this genus because, 

 as originally defined, its only character was the existence of at least 

 two rows of adambulacral spines. This made it synonymous with 

 typical Asterias, which was the evident intention of Perrier, for he 

 restricted Asterias to the monacanthid species. 



In the second place, his first species was A. sulcifera, which he 

 evidently regarded as the type. But Sladen's report was published 

 while his was being put in type. So that in an Appendix, p. K, 160, 

 he admits the priority of Cosmasterias for sulcifera and abandons 

 both Diplasterias and Podasterias (MS. name) and refers lutkeni 

 (non Stimpson) and its congeners to Asterias. This will not hold 



