The Actiuiae of the Plate Collectiou. 227 



but possess 110 acrorliagi and have teiitacles of moderate lengtli 

 Carlgren (1900) has recently pointed out aiiother peculiarity whicli 

 may distinguisli the two species; in Actinia the acrorhagi are 

 situated upon the outer wall of the fosse below the margin, while 

 in Anemonia they arise directly froni the margin. This character 

 may well be combined with that derived froni the tentacles and 

 demands also the Separation of certaiu fornis originally referred to 

 Anemonia. 



Before receiving Carlgren's paper (1900) I had decided that 

 these excluded forms could be well assigued to Kwietniewski's 

 genus Gyrostoma, and I was pleased to find that Carlgren had 

 arrived at the same conclusion. Kwietniewski established his genus 

 for a form, G. hertirigi, which, he regarded as the type of not only 

 a new genus but even of a new tribe, the Isohexactinise, on account 

 of all the primary mesenteries being directives and being associated 

 with a corresponding number of siphonoglyphs. Observations which 

 have been made on irregularities in the number of the directives 

 show that there is no sufficient basis for the tribe which Kwietniewski 

 proposed and furthermore Haddon (1898) has brought forward good 

 reasons for believing that G. hertwigi is really identical with Ane- 

 monia ramsaiji, first described by Haddon & Shackleton in 1893, 

 a form which presents considerable Variation in the number of 

 siphonoglyphes and directives. A. ramsayi is, however, one of those 

 forms which must be separated from the genus Anemonia^ and 

 consequently Kwietniewski's generic name may well be accepted 

 for it and allied forms. I iuclude in the genus Gyrostoma the forms 

 which Carlgren (1900) has assigned to it, namely G. ramsayi 

 (Haddon et Shackleton, 1893), G. hvoiam (Haddon et Shackleton), 

 G. irisiis Carlge. 1900, G. stuhlmanni Caelgr. 1900, and G. dubia 

 Carlgr. 1900, and in addition G. inaequalis (Mo Murrich, 1893) and 

 possibly the form imperfectly described by Fewkes (1889) as Ane- 

 monia stimsonii. 



2. Gi/rostonia selkirkii n. sp. 



No. 91a. Juan Fernandez. 4 specimens. 



309. Juan Fernandez. 6 specimens (young). 



257. Juan Fernandez. 1 specimen (young). 

 The individuals catalogued in the collectiou as 91 a varied con- 

 siderably in size, the mea§urements of the largest being : diameter 



