The meaning of the letters is the same throughout. 



a Oral opening. 



ah Buccal ribs (perradial). 



al Oral lobes (perradial). 



ar Oral grooves (interradial). 



bp Gastral pouches (perradial). 



cs Coronal sinus. 



er Exumbral urticating ribs. 



er' Eight larger principal urticating ribs. 



er" Eight smaller adradial urticating 

 ribs. 



f Gastral filaments. 



ft Taeniola. 



ga Oral stomach (oesophagus). 



gb Basal stomach (apical canal). 



gc Central stomach (principal cavity). 



gn Grooves of the basal stomach (per- 

 radial). 



go Gastral openings (perradial). 



gp Palatine opening (porta palatina). 



gy Pyloric opening (porta pylorica). 



he Cavity of the umbrella corona 



(autrum coronse). 



ii Funnel cavities (interradial). 



hi Septal nodes (cathamma). 



1 Marginal lobes. 

 nib Buccal muscles. 

 one Coronal muscle. 



md' Perradial deltoid muscle. 



md" Interradial deltoid muscle. 



oc Ocelli (pigment eyes). 



p Apical process (umbrella peduncle), 



s Genitalia (or reproductive glands). 



ta Adradial tentacles. 



ti Interradial tentacles. 



tp Perradial tentacles. 



ug Gelatinous substance of the um- 

 brella. 



u w Subumbrella. 



ivr Mesenteries (mesogonia, perradial). 



2 Supporting plate (fulcral lamella). 



Fig. 



1. — The entire Medusa in profile, ten times the natural size. Sixteen darkly 

 pigmented longitudinal urticating ribs project on the exumbrella ; eight longer principal 

 ribs (four perradial and four interradial, er), and eight alternating shorter adradial ribs 

 (er") only strongly developed below. Eight black ocelli (oc) lie at the base of the eight 

 principal tentacles. 



Fig. 2. — Perradial section through the umbrella, ten times the natural size ; in the 

 middle, the pendant oesophagus, fastened at its base by the mesenteries («•;•). 



Fig. 3. — Interradial section through the umbrella, ten times the natural size ; the 

 oesophagus is removed in order to show the genitalia and muscles of the subumbrella. 



Fig. 4. — The subumbrella seen from below, ten times the natural size. In the 

 middle, the perradial oral cross with the frilled oral lobes ; round these the four 

 interradial septal nodes (kn) and the genitalia (g). 



Figs. 5-8. — Transverse sections through the umbrella, at the four heights, given in 

 figs. 2 and 3, by the horizontal lines AB, CD, EF and GH. Figs. 5-7 are ten times, 

 fig. 8 forty times, the natural size. The first transverse section, (fig. 5, GH) is made 

 through the coronal sinus (cs) and coronal muscle (mc) ; the second (fig. 6, EF) through 

 the four septal nodes (In) and mesogonia (wr) ; the third (fig. 7, CD) through the 

 central stomach (gc) ; and the fourth (fig. 8, AB) through the basal stomach (gb). 



