REPORT ON THE DEEP-SEA MEDUSAE. lxxix 



margin of the arms are strongly frilled, their thick midrib is deepened into a groove on 

 the concave endodermal side (oral grooves, " sulci orales," az). The separate folds of the 

 strongly frilled oral margins are laid against one another in such a way that the opposite 

 and contiguous endodermal surfaces of the groove-shaped folds become fused at the points 

 of junction, and transformed into short canals. They open freely on the outside by a 

 funnel at the distal end, towards the inside into the perradial oral groove by a fissure. 

 By fusion of its margins, this oral groove is transformed into a canal (brachial canal). 

 Finally, as the central oral opening becomes fused between the bases of the four oral 

 pillars, and closed by a cruciform " oral suture " (PL XXXII. fig. K), they are physio- 

 logically represented by the numerous " frill funnels " (funnel mouths or sucking mouths). 

 This polystome of the Bhizostomae, therefore, finally rests upon the division into many 

 parts of the originally simple mouth ; the central part becomes fused whilst it is replaced 

 by numerous peripheric oral funnels. The fusion of the oral frills is therefore dependent 

 upon endodermal concrescence or the formation of cathamma, as in the septa between the 

 subumbral radial divisions of the coronal intestine. The endodermal cathammal plate 

 (§ 101) is persistent in both cases. The funnel frills of the BhizostomEe, whose freer oral 

 margin is usually thickly beset with countless digitellae, may produce varied appendages. 

 Thus, urticating clubs are formed by annular fusion (" concrescentia annularis"), (e.g., 

 Cassiopea, Cotylorhiza, System, taf. xxxvii.), whilst the urticating scourges are formed 

 by fissure-shaped fusion ("concrescentia longitudinales "), ("e.g., Cephea, Lychnorhiza, 

 System, taf. xxxiv.). 



§ 115. Palate or palatine opening (" palatum, porta palatina," gp). This is the name 

 applied to the circular constriction by means of which the oesophagus in most Medusae is 

 more or less clearly separated from the central stomach. In many cases it is insignificant 

 or almost obliterated, whilst in others it appears distinctly as a slender neck (comp. in the 

 System, for example, the Anthomedusae, taf. iii., iv., vii. ; the Leptomedusae, taf. x., xii., 

 xiii. ; the Trachomedusae, taf. xvi., xviii. ; the Narcomedusae, taf. xix., xx. ; the Stauro- 

 medusae, taf. xxi., xxii. ; the Peromedusae, taf. xxiii., xxiv.; the Cubomedusae, taf. xxv., 

 xxvi. ; the Discomedusae, taf. xxvii., xxviii., xxx., xxxi., &c). The palatine opening is 

 usually the narrowest part of the principal intestine, and in many cases appears capable 

 of closing voluntarily, so as to debar the water from passing in from the buccal to the central 

 stomach. The form of the palatine opening is usually distinctly cruciform ; the four per- 

 radial limbs of this "palatine cross" forming the upper terminal portion of the " oral cross," 

 project centrifugally towards the outside, their concave abaxial ends being often depressed 

 into a groove, (palatine groves " sulci palatini,") gs, PI. XX. fig. 11). They are sometimes 

 supported by a strong, node-like thickening of the fulcral lamella (palatine nodes, " nodi 

 palatini," gk, PI. XX. figs. 9, 10) The four interradial palatine lips ("labia palatina" #Z), 

 which project centripetally inwards, lie between the palatine nodes (System, taf. x. fio-. 

 6 ; taf. xxiv. fig. 14 ; taf. xxviii. fig. 5, taf. xxxi. fig. 3) ; the gelatinous fulcral plate 



