lxxiv 



THE VOYAGE OF H.M.S. CHALLENGER. 



taeniola are hollowed to their aboral ends by the four endodermal conical funnel cavities 

 of the subumbrella (Pis. XXI., XXII.). The phacelli sometimes form straight lines, 

 sometimes arches more or less waved and have often a complicated course as in 

 Periphyllida3 (Pis. XXL, XXII). The tseniola may form phacelli in all the three 

 chambers of the principal intestine ; in most Acraspeda? the formation of them is limited 

 to the central stomach. In the Peromedusse and in some Stauroniedusse, they are 



Fig. I. Pcrkolpa quadrigata ( Peromedusce, Perieolpida?). 

 Interradial section. (ug) Gelatinous umbrella, (cs) Coronal sinus (cs' proximal part, cs- distal part). 

 (s) Genitalia, (hi) Cathammal nodes, (go) Gastral openings, (md!) Deltoid muscles, (roc) 

 Coronal muscle, (ft) Tamiola. (gb) Niches of the basal stomach between the tamiola. (gy) 

 Pylorus, (gc) Central stomach, (gp) Palatine opening, (ga) Buccal stomach (oesophagus), (am) 

 Oral margin, (oi) Sense clubs (interradial). (oa) Ampulla; at their base, (bu) Horseshoe-shaped 

 canal of the marginal lobes (la). (M) Peronia between the two limbs of the canal (bl). (tp) 

 Tentacles (perradial). 



strongly developed in the basal stomach, in the Cubomedusse and Peromedusae in the 

 buccal stomach : their terminal processes are the barbous filaments of the Peromedusae 

 (PI. XX. figs. 9-11, af). In the Discomedusse, the phacelli assume a definite topo- 

 graphical (and perhaps also physiological) relation to the reproductive glands ; they he 

 there on the inner surface of the subumbral gastral wall, on the inner or axial margin 

 of the frill-shaped, folded genitalia, whose winding course they follow. 



