571 Mr. W. K. Fisher on the 



LXXV. — On the Generic Name Stolasterias, Sladen. 

 By Walter K. Fisher. 



In that invaluable work by Sladen on the Asteroidea of 

 the * Ciiallcnger^ Expedition (Zoolooy, xxx.) we find tlie 

 first systematic attempt to subdivide the laroe and unwieldy 

 genus Asterias into smaller and more natural i^roujjs. Sladen 

 considered these groups to be subgenera ; but since then all 

 liave been accorded generic rank by Perrier and others. 

 Some of Sladcn's groups (as, for example, Stolasterias) have 

 been again divided into narrower genera. In this division 

 unnecessary confusion has been caused by the renaming of 

 previously named genera and tlie transference of Stolasterias 

 to a slightly different group — in other words, by giving it a 

 new type species. 



To begin at the beginning, the type of Stolasterias, Sladen, 

 is Asterias tenuispina, Lamarck. In an article entitled 

 " Notes on the Eadiata in the Museum of Yale College, witli 

 Descriptions of new Genera and Species ''*j p. 2i8, Verrill 

 describes a new genus and species, Coscinasferias muricata, 

 from New Zealand, giving a separate diagnosis for the genus., 

 This species Sladen considered as strictly congeneric with 

 A. tenuispina, for he placed it under the synonymy of 

 Asterias {Stolasterias) calamaria, Gray, the third species 

 (/. c. p. 583) of his " Asterias <ewM«-spina group.-*' It is 

 curious that he did not recognize the claims of the generic 

 name, which should have been given to the subgenus instead 

 of a new designation, Stolasterias. In other words, the 

 genus Stolasterias, including tenuispina, calamaria, gemmi- 

 lera, volsellata, stichantha, glacialis, and other species, must 

 be called by tlie mucli older name Coscinasturias, Verrill. 



In 1894 Perrier j divided Sladen^s group into three 

 gg„era — Cuscinasterias, Verrill (type calamaria), Poly asterias ^ 

 Perrier (type, by inference, tenuispina), Stolasterias, Sladen, 

 emended (type glacialisl). In 1896 J he added another 

 genus, JJistolasterias (type stichantha, Sladen), for the five- 

 and six-rayed species with two spines to each adambulacral 

 plate. Siiice tenuispina had already been made the type of 

 Stolasterias, the name Folgasterias was superfluous and falls 



* Trans. Conn. Academy, i. part 2, Fob. 1867. 

 t Exped. ' Travailleur ' et ' Talisman,' Echinodermes, p. 108. 

 X " Contiib. a I'Etude des Stellerides de I'Atlantique Nord," Res. 

 Canipag. Scientif. du rrince de Monaco, fasc. xi. p. 3-1. 



