REPORT ON THE DEEP-SEA MEDUSAE. 



lxxxi 



predominates in two orders, in the Narcoruedusse among the Craspedotae (System, taf. 

 xix., xx.), and in the Discomedusse among the Acraspedse (System, taf. xxvii.-xl.). The 

 horizontal axis of the central stomach is usually much larger than the vertical, and the 

 lenticular flat central stomach does not project at all, or only slightly into the subumbral 

 umbrella cavity ; its peripheric margin is cut away like a lens. As the basal stomach, 

 and, consequently, the pylorus, are wanting, the flat upper wall or cover of the stomach is 



Fig. L. Cannorhiza conncxa (Discomedusa;, Versuridie). 



Subliminal view of the umbrella. The arm disk with the eight oral arms is removed, as the four per- 

 radial arm pillars (ab), which connect the umbrella disk and the arm disk, are cut through, (oi) 

 Interradial sense clubs. (um) Umbrella margin (turned over inwards), (s) Genitalia, wx) 

 Gelatinous cross of the gastrogenital membrane, (gy), (gh) Peripheric limbs of the gelatinous 

 cross, (ug) Peripheric umbrella corona, (cc) Coronal canal, (cd) Pillar canals, (ca) Adradial 

 canals, (ft) Interradial canals, (cp) Perradial canals. 



formed immediately by the discoid gelatinous substance of the umbrella ; the lower wall 

 or bottom of the stomach is supported by a thick gelatinous plate of the subumbrella, and 

 communicates in the middle through the palatum with the oesophagus (Pis. XXVI.- 

 XXXI. ). 



§ 117. Cruciate chambers and cruciate columns ("camera? cruciatae" et "columnar 

 cruciatas "). In many Medusae of different groups the quadrate central stomach assumes 



(ZOOL. CHALL. EXP. PART XII. — 1881.) M I 



