REPORT ON THE SIPHONOPHOR^E. 89 



Subclass II. SIPHONANTH^E. 



Order II. CALYCONECT^, Haeckel, 1888. 

 (Pis. XXVII.-XLII.) 



Diphyidte, Eschscholtz, 1829, 1, p. 122. 

 Cahjcoplwridx, Leuckart, 1854, 8, p. 256. 



Definition. — Siphonophorae with one or more nectophores, without pneumatophore, 

 and without palpons. Nectosome always without pneumatocyst, represented only by 

 the nectophores. Siphosome either a single siphon (Monogastricae) or a long tubular 

 stem, bearing a series of equidistant siphons, separated by free internodes (Polygastricse). 

 Each siphon with a single tentacle bearing a series of tentilla or lateral branches ; each 

 tentillum with a cnidosac and a simple terminal filament. 



The order Calyconectae, hitherto usually called Calycophoridae, comprises all Siphono- 

 phorae without pneumatophore. No doubt this large group is very natural ; it differs 

 from all the other Siphonophorae, not only in the complete absence of the important 

 pneumatic apparatus, but also in a number of other peculiarities. The primary larva 

 develops first a nectophore (in the others a pneixmatophore). The siphons have always 

 the same structure, and so also the single tentacle, which is attached to each siphon ; it 

 bears a naked cnidosac (without involucrum) of a constant structure. The long tubular 

 stem of the polygastric Calyconectas always bears a single row of ordinate cormidia, 

 separated by naked free intervals. Each cormidium constantly bears a single siphon 

 only, and a single tentacle. Palpons and paipacles never occur in the Calyconectae. 



History. — Eschscholtz, in his fundamental work, 1 divided the order Siphonophorae 

 into three natural families ; the first of these, Diphyidae, differs from the two other 

 (Physophoridae and Velellidas) in the complete absence of any float filled with air. He 

 distinguished six different genera ; three of these (Eudoxia, Ersasa, Aglaisma) are 

 monogastric ("with a single suctorial tube"); the three others (Abyla, Cymba, Diphyes) 

 are polygastric (" with a long digestive tube bearing numerous suctorial tubes "). 



The oldest known of these six genera was Diphyes, founded by Cuvier in 1817, 3 

 upon an apparently double animal, or twin-zoophyte, of which Bory had given the first 

 figure in 1804 under the name Biphora bipartite, (13) ( — Diphyes dispar, Chamisso). 



Lesson adopted in 1843 (3, p. 424) the system of Eschscholtz, and divided the family 

 Diphyidae also into Monogastricae and Polygastricaa. But he distinguished a greater 

 number of genera and subgenera (partly constituted already in 1827 to 1833 by Quoy 

 and Gaimard, 2 and 20). Lesson collected all the scattered descriptions of Diphyidae 



1 System der Acalephen, 1829, p. 122. 2 Regne animal, edit, i., tome iv. p. 61. 



(ZOOL. CHALL. EXP.— PART LXXVII. 1888.) Hhhh 12 



