REPORT ON THE SIPHONOPHOR^. 



323 



they are irregularly scattered. The gonostyle, or the axial stem of each gonodendron, is 

 more or less branched, in the larger species with very numerous branches; each branch is 

 monostylic and exhibits the same structure (PI. XXIII. fig. 8), as is common to all 

 Cystonectse (compare above, p. 313). The distal end of the branch bears a spindle-shaped 

 palpon with numerous cnidocysts (fig. 8, gq), and at its base a single large medusiform 

 gynophore (f) surrounded by a corona of club-shaped androphores (A). 



Synopsis of the Genera of Rhizophysidse. 



I. Subfamily Caxnophysid^. 



Cormidia ordinate, separated by free internodes. Gono- 

 styles attached to the stem immediately on the base of 

 the siphons. 



II. Subfamily Linophysida;. 



Cormidia loose. Gonostyles 

 attached to the inter- 

 nodes of the stem, scattered 

 between the siphons. 



Tentacles simple, without 

 tentilla ; or with simple, 

 unbranched tentilla. 



Tentacles always with a 

 series of tentilla, all or 

 some of which are bran- 

 ched. 



\ Tentilla simple, not bran- 

 ched, 



Tentilla trifid, with three 

 terminal branches, 



Tentilla wanting, tentacles 

 simple, . 



Tentilla simple, unbran- 

 ched, 



f Tentilla all trifid, with three 

 terminal branches, 



j Tentilla polymorphous, 

 partly simple, partly 

 branched or palmate, 



66. Aurophysa. 



67. Cannophysa. 



68. Linophysa. 



69. Nectophysa. 



70. Pneumophysa. 



71. Rhizophysa. 



Genus 66. Aurophysa? Haeckel, 1888. 



Aurophysa, Hkl, System der Siphonophoren, p. 44. 



Definition. — Khizophysidae with ordinate cormidia and free internodes of the stem, 

 the gonostyles being attached on the base of the siphons. Tentilla simple, unbranched. 



The genus Aurophysa comprises those Rhizophysidse which may be regarded as the 

 oldest and simplest forms of that family. The long tubular stem is divided into 

 numerous equidistant nodes ; attached to each node is an ordinate cormidinm, composed 

 of a siphon with its tentacle and a monostylic gonodendron. The long internodes 

 between the cormidia are naked, as in Apolemia and the polygastric Calyconectse. 

 Aurophysa agrees in this important character with the following Cannophysa 

 (PI. XXIV.) ; both genera together represent the subfamily Cannophysidse. Aurophysa 

 differs, however, from Cannophysa in the form of the tentilla, which in the former are 

 simple cylindrical filaments (as in Nectophysa, PI. XXIII. ), in the latter trifid, with 

 three terminal branches. I observed an interesting species of this genus, Aurophysa 

 orclinata, in December 1881, in the Indian Ocean, on the coast of Ceylon (off Colombo); 



1 Aurophysa = Air-bladder, &vp*, (pvox. 



