320 Mr. J. W. Fewkes on a neio Phijsophore. 



resemble those of Athoryhia'^ rosacea^ Koll. The sacculus 

 is uncoiled, curved, and armed with powerful nematocysts. 

 The involucrum is rudimentary. 



Gonophores. — Clusters of male and female gonophores are 

 found at the base of the hydrocysts. Monoecious. An ex- 

 ceptionally large cluster of female gonophores is found at the 

 point s. 



Summary of Exceptional Features m Ploeophysa. 



1. Existence of the hood (/«). 



2. Portion of the stem (axis) which ordinarily bears 



polypites (polyp-stem) is reduced to a globular sac. 

 The nectostem, or the part of the stem which gene- 

 rally bears nectocalyces, is modified into a hood {k). 



3. Nectocalyces and hydrophyllia are wanting. 



II. Conclusions in regard to the Affinities o/" Ploeophysa. 



1. It is the type of a new family, for which the name 

 Ploeophysidaj is suggested. 



The affinities of Ploeophysa are somewhat difficult to make 

 oat. As in the families to which Physalia, Velella, and Rhizo- 

 physa respectively belong, nectocalyces and hydrophyllia are 

 M^anting, The tentacular knobs are unlike those of any of 

 these families. There is, however, a remote likeness of the 

 tentacular knobs of Ploeo'physa to those of Plilzophysa gra- 

 cilis, Fewkes f ; but in this genus the stem is elongated and 

 not globular, as in Ploeophysa. While the tentacular knobs 

 somewhat resemble those of Athoryhia rosacea, unlike any of 

 the Anthophysidai the Plceophysidaj are destitute of hydro- 

 phyllia or covering-scales. 



The absence of nectocalyces separates Ploeophysa from the 

 order Auronecta^ of Hackel J, although it is not impossible 

 that the hood is homologous with the aurophore of the last- 

 mentioned writer. 



With the Angelidae, a family which includes Angela and 

 Angelopsi's, Ploeophysa has close resemblances, but differs 

 from it in the character of the hood. 



* The Athorybia with two kinds of tentacular knobs described by me 

 as Athoryhia fwmosa is referred by Hasckel to Ayithophysu, Mert. I 

 accept his suggestion that it is not an Athorybia, but find it diflerent 

 from Anthophysa. It is probably a new genus, Diplorybia, Fewkes. 



t Bull. Mus. Comp. Zool. vol. ix. no. 7, p. 270, pi. vi. fig. 5. 



X Of the three genera of this order Stejjhalia is Avithout tentacular 

 knobs ; while Auralia and lUiodulia, according to Hajckel, have knobs like 

 Forslmlia. 



1 



