RHIZOPHYSINAE. 317 



Rhizophysaliae Chun, 1SS2. 



According to Schneider ('98, p. 164), and to Lens and Van Riemsdijk, 

 (:08, p. 100), the two main subdivisions of this group, Rhizophysids and Physa- 

 Uds, are too closely alhed to each other to deserve the appellations of suborders 

 "Rhizoidea" and " Physaloidea " given them by Chun. However, they form 

 well-marked families. Haeckel divided the Rhizophysids (exclusive of the 

 Bathyphysids which he classed among the Physophorae) into four famihes, 

 Cystaliidae, Rhizophysidae, Salaciidae, and Epibuliidae. But as Chun ('97b) 

 has pointed out, the Cystaliidae are merely the young stages of Epibulids, while 

 Salacia, the only genus of Salaciidae, is so closely allied to Rhizophysa that it 

 certainly is of not more than generic rank. Chun himself recognized two fami- 

 lies of Rhizophysids, Epibuliidae and Rhizophysidae, dividing the latter into 

 two subfamilies, Rhizophysinae and Bathyphysinae. Schneider unites all 

 these in one family, but Lens and Van Riemsdijk, who do not give any com- 

 plete scheme, mention two families, Rhizophysidae and Bathyphysidae. It 

 seems to me that Schneider's reduction goes too far, especially in the case of 

 the Epibuliidae, which are sharply demarked from their allies by a very much 

 shortened stem, exactly as are the Nectaliinae from the typical Agalmidae (p. 289) . 

 On the other hand it would certainly be erroneous to class the Epibuhds and 

 Bathyphysids as subdivisions of as high rank as the Physalids, for they are too 

 closely allied to the Rhizophysids by the presence of hypocystic villi in the 

 pneumatophore, and by the structure and arrangement of the appendages. 

 They are therefore regarded, in this Memoir, as subfamilies, Rhizophysinae, 

 Bathophysinae, and Epibuliinae, of the Rhizophysidae. 



Rhizophysidae Brandt, 1835. 

 Rhizophysinae Chun, 1897. 



Two genera of Rhizophysinae can be distinguished, Rhizophysa and Sala- 

 cia, the former with monogastric, the latter with polygastric cormidia. Schneider 

 ('98), it is true, has united the two, but it can not be ciuestioned that this differ- 

 ence in the structure of the cormidia is more important than the differences in 

 the tentilla usually considered of specific significance in Rhizophysa. 



Salacia is monotypic. I have not had an opportunity to study S. uvaria 

 Fewkes. 



