EEPORT ON THE SIPHONOPHOR.E. 133 



Cormidia (figs. 3, 5). — The cormidia, or the single "groups of persons," disposed 

 regularly in metameric order, are sessile eudoxomes, the sexual organs becoming ripe on 

 the stem. There are no free Eudoxise developed. In two of the three observed specimens 

 all the eudoxomes were female (figs. 3, 4), in the third specimen male (figs. 5, 6). 

 Mitrophyes, therefore, is one of the rare dioecious Siphonophorae. Each eudoxome is 

 composed of two medusomes, one sterile (siphon with tentacle and bract) and one fertile 

 (the gonophore). 



Lateral Bracts (figs. 3, b, 5, b). — The bract of each cormidium is an oblongish scale, 

 nearly of the form of a bisected egg. Its proximal part is rounded and attached to the 

 stem (a), its distal part is obtusely pointed. The convex umbrella is smooth. Its sub- 

 umbrellar cavity covers the included siphon and gonophore only partly. There is no 

 phyllocyst or bracteal canal. 



Siphon (figs. 3, s, 5, s). — The siphon of each cormidium is placed between bract 

 (dorsally) and gonophore (ventrally). Its pedicle is very short, the basigaster (sb) very 

 thickened, nearly spheroidal, with a dense accumulation of cnidocysts. The stomach (sm) 

 is ovate, thick-walled, and includes numerous scattered large cnidocysts (kc) in the 

 exoderm ; its entoderm possesses hepatic stria?. The proboscis (sr) is very muscidar, 

 cylindrical, with a simple circular mouth-opening (so). 



Tentacle (figs. 1,3,5, t). — The single long tentacle which arises from the pedicle of each 

 siphon bears a great number of tentilla. The cnidosac of each tentillum (fig. 8) is kidney- 

 shaped, and bears at its proximal base only two pairs of large ovate cnidocysts (kg). The 

 terminal filament is about as long as the pedicle of the tentillum (figs. 5, 8). 



Gonophores (figs. 3, f, 4, female ; figs. 5, h, 6, male). — Each cormidium bears only a 

 single gonophore without accessory sexual bells. They possess the usual shape of 

 medusoid gonophores in Calyconectse, and are about as large as the siphon. The sper- 

 maria (figs. 5, 6, lis) are more longish than the ovaria (figs. 3, o, 4). The umbrella 

 possesses in both sexes four regular radial canals, which are united by a ring-canal at 

 the basal ostium (uo). 



Genus 21. Cymbonectes, 1 Haeckel, 1888. 



Cymbonectes, Hkl., System der Siphonophoren, p. 34. 



Definition. — Monophyidaa with an angular, pyramidal nectophore, and an open 

 hydrcecial groove on its ventral side ; the latter includes the siphosome, which is 

 incompletely protected by two overlapping lateral wings. Bracts spathiform, with an 

 open ventral fissure, and a simple ovate phyllocyst. 



The genus Cymbonectes has hitherto been known by a single species only, described 

 in 1859 by Huxley as Diphyes mitra, and taken only once in the Indian Ocean. 2 



1 Cymbonectes = Swimming boat, nvfifion^KTrn. - 9, p. 36, pi. i. fig. 4. 



