250 



C(ELENTERATA. 



To these is usually added a funnel or umbrella-shaped hydrophyl- 

 liurn (fig. 192). These groups of individuals may in some Diphyids 

 become free, and assume a separate existence as Eudoxia (fig. 193). 

 The gonophores contain numerous ova in the manubrium, which 

 often projects as a cone from the aperture of the bell. In the larva 

 the upper nectocalyx is the first formed. 



Fam. Hippopodidae. The swimming column has two rows of nectocalyces, 

 and is situate on an upper lateral branch of the stem. The male and female 

 gonophores are grouped in clusters and are situate at the base of the nutritive 

 polyp. Glela Hippopus Forsk., Mediterranean. 



Fam. Diphyidae. With two very large nectocalyces at the upper end of the 

 stem and opposite to each other. Dipliyes acuminata Lkt., dioecious ; with 

 Eudoxia campanulata. Alyla pcntagona Esch., with 

 Eudoxia cuboides, Mediterranean. Spliceronectes 

 J!vixl. MonopJiye8 Cls., Sp. (/racilis Cls. with Diplo- 

 ^Jiysa inermis. Mediterranean. 



(4) Sub-order : Discoidece. Stem compressed 

 to a flat disc, with a system, of canal-like spaces 

 (central cavity). Above lies the pneurnatocyst 

 in the form of a disc-shaped reservoir of car- 

 tilaginous consistence composed of concentric 

 canals opening to the exterior. The polypoid 

 and medusoid appendages are situate on the 

 under side of the disc. In the centre is a large 

 nutritive Polyp, around which are a number of 

 smaller ones. To the base of these small Polyps 



FIG. 193. -Part of a T>i- are attached the gonophores. The dactylozooids 

 piiy-.d (after R. Leuck- are no t far from the edfife of the disc. The 



art). D, Hydropliyl- , 



lium ; GS, genital gonopnores are set tree as small Medusce (Cliry- 

 nectocaiyx ; p, polyp somitra), which do not produce the generative 



with tentacles. The . ' . 



individual groups se- material till long after separation. 



parate as Eudoxia. 



Fam. Velellidae. Velolla spirans Esch., Mediter- 

 ranean. Porplta mcdlterranea Esch. 



Order 3. SCYPHOMEDUS^E = ACALEPHA.* 



Medusce of considerable size, with gastric filaments. The edge of the 

 umbrella lobed. The sense organs covered. The embryonic stages are 

 not hydroid stocks but Scyphistoma and Strobila forms. 



The Medusce of this order are distinguished from those of the 

 hydroid group by their considerable size and the great thickness of 



* Besides the works of Brandt, L. Agassiz, Huxley, Eysenhardt, compare 

 v . Siebold, " Beitrage zur Naturgeschichte der wirbellosen Thiere," 1839. M. 



