62 THE VOYAGE OF H.M.S. CHALLENGER. 



Lucernaria bathyphila, therefore, furnishes the first example in the order of Stauro- 

 medusoe of a complicated reproductive gland with lobed sacs and branched hollow spaces ; 

 and this, and other peculiarities already mentioned of our deep-sea species, justify its 

 being raised to the type of a separate species, Lticernosa. Both the separate sacs 

 and the follicles of which they are composed are enclosed in a thin structureless " mem- 

 brane propria," a direct process of the gelatinous fulcral plate of the subumbrella. The 

 sacs (figs. 17, 18, sk) project freely from the subumbral wall of the radial pouches, on 

 whose endodermal surface they are placed, into the hollow space of the pouches ; their free 

 abaxial surface is covered by the ciliated endodermal pouch epithelium, whilst their 

 fixed axial surface is divided from the ectodermal pouch epithelium (qiv) by the thick 

 gelatinous plate of the subumbrella (figs. 17, 18, tig). There is, therefore, no doubt that 

 the ova are developed from the endodermal cells of the sacs, which has no connection 

 with the subumbral ectoderm. 



Order VI. PEROMEDUS^, Haeckel, 1877. 



Acraspedae with four interradial rhopalia, containing an auditory club with an endo- 

 dermal otolite sac and one or more eyes, four perradial tentacles or twelve tentacles (four 

 perradial and eight adradial), eight adradial or sixteen subradial marginal lobes. Stomach 

 surrounded by a subumbral coronal sinus, whose division into four radial gastral pouches is 

 only indicated by four small interradial septal nodes ; eight or sixteen coronal pouches on 

 the distal margin of the coronal sinus ; two lateral lobe pouches from each coronal pouch, 

 and in the middle between the lobe pouches, a pouch for the tentacle or the rhopalium. 

 Genitalia, eight adradial horseshoe-shaped swellings which lie in the subumbral wall of 

 the coronal sinus, are developed from its endoderm and partly project into its cavity. 



Family, Periphyllid^e, Hseckel, 1877. 



PERiPHYLLiDiE, Hfecke], System der Medusen, 1879, p. 415, plate xxiv. 



Peromedusas with twelve tentacles (four perradial and eight adradial), with four inter- 

 radial rhopalia and sixteen subradial marginal lobes (eight tentacular and eight ocular). 

 Exumbrella with sixteen pedalia, and a coronal muscle with sixteen coronal areae (four 

 perradial, four interradial and eight adradial), a coronal pouch between each pedalium 

 and each coronal area. Marginal festoon canal formed of thirty- two lobe pouches. 



Sub-family, Pepjphemid^e, Haeckel, 1880. 



Periphyllidaa whose four interradial funnel cavities are not limited to the central 

 stomach but also traverse the basal stomach, wholly or partially. 



