REPORT OX THE SIPHONOPHORJE. 260 



character with the monogastric Athoridae, but differs from this closely allied family in 

 the possession of numerous siphons. 



The first described and the best known type of Anthophysidae i3 the Mediterranean 

 Athorybia rosacea. It was discovered by Forskal, who figured it under the name 

 Physophora rosacea as early as 1775 (11, Tab. xliii. fig. B). Two< other closely 

 related species, taken in the Strait of Gibraltar, were described by Quoy and Gaimard 

 as Rhizophysa heliantha and Rhizophysa melo (2Q), and afterwards placed by the same 

 authors in the genus Stephanomia (2). These three species together were united in 

 the genus Athorybia by Eschscholtz (l, p. 153) in 1829. A similar fourth form, 

 taken in the Northern Pacific, was described by Mertens as Anthophysa rosea (25, 

 p. 36), and Brandt in 1835 established for all these together the family Anthophysidae. 



The first accurate anatomical description of Athorybia was published in 1853 by 

 Kolliker (4, Taf. vii.), and supplemented by Huxley in 1859 (9, pi. ix.). He called 

 the family represented by it Atkorybidae. The genus Anthop>hysa differs from the 

 former in the possession of two kinds of tentacular knobs. An American species of 

 this genus was afterwards accurately described by Fewkes, under the name Athorybia 

 formosa (44, p. 271, pis. v., vi.). The development of the fertilised egg was examined 

 in 1866 by myself (84, p. 88, Taf. xiv.). 



The Anthophysidse, or Athorybidae, are among the most beautiful and most delicate 

 Siphonophone. But they are in general rare, and owing to their small size and 

 fragility their anatomical investigation is difficult. Some interesting new forms of this 

 family, which I was able to examine living in the Mediterranean, the Atlantic, and the 

 Indian Ocean, have enabled me to complete their anatomical knowledge (Pis. XL, XII.). 



Truncus. — The ccenosome or common stem is in all Anthophysidas a small ovate, 

 pyriform, or flatly conical vesicle. Its apical (proximal or superior) half is the necto- 

 style, includes the pneumatocyst, and bears the corona of bracts ; its basal (distal or 

 inferior) half is the siphostyle, and bears in the periphery a corona of very numerous 

 palpons, in the central part a smaller number of siphons, tentacles, and gonostyles. 



Although the general appearance of the corm in all Anthophysidas is radial, 

 nevertheless the fundamental form of the trunk is always bilateral, as in all the other 

 Siphonanthse. The series of buds, which is visible as well in the nectosome (PI. XII. 

 fig. 9, ib) as in the siphosome (fig. 9, is), marks the ventral median line of the trunk. 



Cormidia. — The numerous polymorphous persons or medusomes, which compose 

 the corm of the Anthophysidse, are arranged around the common central trunk in a 

 certain regular manner. This has hitherto escaped all observers, owing to the small 

 size and the great delicacy of the object. The specimen of Anthophysa darwinii, 

 which I found in the Challenger collection, and which is figured in PI. XII. figs. 7—9, 

 exhibited this regular arrangement of the cormidia more distinctly than the smaller 

 species of Athorybia hitherto described. In general this ordinate structure seems to be 



