MEDUSA. 41 



into a very broad adhesive disc, by which the animal fixes itself to the bottom of the 

 sea. There is no true stalk, and only a narrow constriction separates the umbrella 

 from the adhesive disc. The peduncle is hollow and consists of one single chamber, 

 which is partly filled up with the bulbous enlargements of the four tseniolse. The 

 internal longitudinal muscle bands of the taeniola terminate at the constriction, and 

 do not proceed into the peduncle itself. In the peduncle the tseniolse are wholly 

 gelatinous, as in Lucernaria campanulata. The jelly or mesoglaea on the bottom of the 

 peduncle and of the tseniola is permeated by small branched canals which come from 

 the hollow chamber. The ectodermal surface of the peduncle is divided up into 

 numerous small lobes and irregular folds, which are flattened out on the side used 

 for attachment. 



The mouth has a large, thin, leaf-like margin which is beautifully arranged in folds. 

 It opens through a small constricted oesophagus into the stomach, which is rather 

 small for the size of the umbrella, and is well packed with gastric filaments. The 

 funnel cavities are large and penetrate about half the length of the stomach. The 

 gastric filaments are very much crowded together on the tseniolse. As a rule they are 

 branched close to their base, and occasionally near their distal ends. They have the 

 appearance of flat slender ribbons, about 5 to 10 mm. in length. 



The arms are short and thick, and are about equal distances apart. Upon each 

 arm is situated a large oval cluster of short capitate tentacles, the number of which is 

 estimated up to about three hundred. The capitate apex of the tentacle is crowded 

 with long nematocysts. The tentacles forming the outer row, on the ex-umbrellar side, 

 are provided with a lateral adhesive pad (Plate V., fig. 4), and some of the tentacles 

 in the second row have also similar pads. Lucernaria campanulata has adhesive pads 

 of similar structure on the tentacles occupying the same position as those of Lucernaria 

 vanhoeffeni. 



The gonads extend from the stomach to the base of the arms, forming fairly broad 

 bands. Each band consists of a large number of elongated sacs (Plate V., fig. 5). 

 Transverse and longitudinal sections were cut of the sacs, but only a diagram 

 (Plate V., fig. 6) of their structure is given, as the preservation was too bad for the 

 drawing of an actual section. Each sac consists of a large number of little branched 

 or unbranched tubes, lined with endoderm and separated from one another by 

 mesoglsea. All the tubes are connected with a main duct, which runs the whole length 

 of the sac and opens at one end to the exterior. The blind end of the tubes is blocked 

 with cells, amongst which small ova are clearly visible. It is amongst these cells at 

 the end of the tubes that the gonads develop, and when the ova reach a certain size 

 they pass down the tubes into the main duct which opens into the gastric pouch. In 

 the male the small tubes are not so well defined. There are masses of sperm mother- 

 cells, which are connected with tubes leading into a large broad duct filled with 

 spermatozoa. The structure of the gonads of Lucernnrin ranhoeffeni is similar to that 

 described by Autipa for L. waiter i. 



