REPORT ON THE SIPHONOPHORvE. 



323 



they are irregularly scattered. The gonostyle, or the axial stern of each gonodenclron, is 

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

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

 Cystonectas (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 (h). 



Synopsis of the Genera of Rhizophysidte. 



I. Subfamily Cannophysid;e. 



Cormidia ordinate, separated by free internodes. Gono- - 

 styles attached to the stem immediately on the base of 

 the siphons. 



Tentilla simple, not bran- 

 ched, 



Tentilla trifid, with three 

 terminal branches. 



II. Subfamily Linophysidjj. 



Cormidia loose. Gonostyles 

 attached to the inter- 

 nodes of the stem, scattered 

 between the siphons. 



f Tentilla wanting, tentacles 

 Tentacles simple, without I simple, . 

 tentilla ; or with simple, -! 



unbranched tentilla. | Tentilla simple, unbran- 



ched, 



Tentacles always with a 

 series of tentilla, all or 

 some of which are bran- 

 ched. 



' Tentilla all trifid, with three 

 terminal branches, 



Tentilla polymorphous, 

 partly simple, partly 

 branched or palmate, 



66. Aurophysa. 



67. Oannophysa. 



68. Linophysa. 



69. Nedophysa. 



70. Pneumophysa. 



71. Rhizophysa. 



Genus 66. Aurophysa, 1 Haeckel, 1888. 

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



Definition. — Rhizophysidae 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 Rhizophysidae 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 cormidium, 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 Calyconectae. 

 Aurophysa agrees in this important character with the following Cannophysa 

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

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



1 Aurophysa = Air-bladder, oivpa, (fvatt. 



