E. W. BERGER ON THE CUBOMEDUS^. 13 



could pulsate well enough but with little progress. (See above under 

 Velarium and Frenula.) 



An isolated tentacle is capable of squirming contractions, and 

 when stimulated at either end, it would contract wholly or in part 

 only. 



The pedalia, then, it would seem, serve also as a steering apparatus, 

 for which they are admirably fitted, considering their blade-like 

 thinness. 



Considering, now, the reflexes noted under this head and the 

 preceding one, we find that there is an intimate nervous connection 

 between the velarium and frenula, subumbrella, sensory clubs, nerve, 

 and a single pedalium, on the one hand, and the pedalia on the other 

 hand. This is born out fully, furthermore, by the histological evidence 

 (See Introduction and "Cubomedusae"). Considering the subumbral 

 plexus of ganglion cells and fibers, including the velarium and the 

 frenula, which is in connection with the nerve ring and this again 

 with the sensory clubs and the interradial ganglia at the bases of 

 the pedalia, we have a basis for these reflexes. While Con ant failed 

 to demonstrate nerves ("Cubomedusas") from the interradial ganglia 

 to the pedalia, yet, that a nervous connection exists between the 

 pedalia and the bell is well shown by his physiological experiments. 

 I have, furthermore, demonstrated ganglion cells under the ectoderm 

 of the tentacles (see Histology). 



Romanes obtained quite similar results in the Hydromedusa?. He 

 found that when a tentacle of Sarsia was slightly stimulated, it alone 

 would contract, but when it was more strongly stimulated the other 

 tentacles also would respond as also the manubrium. I find no evidence 

 in Conant's notes of any such response of the manubrium of Charybdea, 

 except when the clubs were cut off. 



The reflex obtained on stimulating the subumbrella of Charybdea, 

 when the pedalia would contract, is somewhat different from that 

 obtained by Romanes, who found that the most sensitive part of the 

 subumbrella in producing a reflex of the margin was at the junction 

 of the manubrium to the bell and that the subumbrella below this 

 point did not give the reflex. 



Stomach, Suspensoria, Proboscis, Subumbrella Experiments 12, 18, 

 19, 24-26, 29, 31. The proboscis and the stomach with the phacelli 

 when cut out, contracted with or without the lips removed. The 

 isolated lips also contracted (twitched). 



