REPORT ON THE SIPHONOPHOR^E. 141 



Siphosome (figs. 4-6, i). — The common trunk bears In its upper part very numerous 

 buds of cormidia (i), in its lower part ten to twelve or more well-developed eudoxomes. 

 These are soon detached from the stem and swim about as free Eudoxise of the special 

 form represented in PI. XLII. as Cuboides crystallus (compare their description above, 

 p. 112, Genus 13). When fully contracted the entire siphosome, with all cormidia, is 

 hidden in the hydrcecium (figs. 4-6). 



Family VII. Diphyid^e, Eschscholtz, 1829 (sensu restricto). 



Diphyulse, Esch., System der Acaleplien, 1, p. 122. 



Definition. — Calyconectae polygastricsB, with two nectophores at the apex of the long- 

 tubular truuk. Cormidia ordinate, eudoxiform, separated by equal free internodes, each 

 siphon with a bract. 



The family Diphyidse, as defined in my system, comprises only those polygastric 

 Calyconectse which bear two permanent nectophores on the top of the stem. I exclude, 

 therefore, those forms, formerly united with them, which possess only a single nectophore 

 (Monophyidse). I exclude, further, on practical grounds, the monogastric independent 

 forms, which are connected with the Diphyidae by metagenesis, the so-called Diphyo- 

 zooids, the families (IV. and V.) Eudoxidse and Ersseidas. The Diphyidae are very 

 common in all the seas of the world, far more frequent than all other Siphonophorae, and 

 richer in different species than the other Calyconectae. 



The first Diphyid was described in 1804 by Bory under the name Biphora bipartita 

 (13, vol. i. p. 134). Cuvier founded for it the genus Diphyes (in 1817, 91), and 

 Chamisso figured the same as Diphyes dispar (16, p. 365, Tab. xxxiii. fig. 4). 



The naturalists of the "Astrolabe." Quoy and Gaimard, discovered in 1826, in the 

 Straits of Gibraltar, a greater number of Diphyidse, and distinguished in this family 

 six different genera: — 1. Diphyes (campanulifera) ; 2. Calpe (jpentagona) ; 3. Abyla 

 (trigona) ; 4. Cymba (sagittata) ; 5. Enneagonum (hyalinum) ; and 6. Cuboides 

 (vitreus) (20). These and some other Diphyidse were described and figured by the same 

 authors in 1833 in the Zoophytes de l'Astrolabe (2, pp. 81-106) as fifteen different 

 species of the genus Diphyes, nearly every species of which is now the type of a special 

 genus. 



Eschscholtz (1, p. 122) gave the first accurate description and a better systematic 

 arrangement of the Diphyidse ; they form, in his System der Acalephen, the first of the 

 three large families of Siphonophorse. He distinguished six genera ; three of these 

 (Eudoxia, Ersasa, Aglaisma) are monogastric, and form now our family Eudoxidre (p. 103); 

 the three others (Abyla, Cymba, Diphyes) are polygastric ; one of these (Cymba) is 

 according to my observations a Monophyid, so that only Diphijes and Abyla remain 

 as types of true Diphyidae. 



