MEDUSA. 57 
gelatinous parts remain. The basal portion of the arm, close to the mouth, is very 
much compressed laterally, resembling a thick fleshy leaf, about 130 mm. broad and 
about 20 mm. thick. 
The lower wall of the stomach is thick and strong for carrying the weight of 
the oral arms. In it there are four interradial genital openings, which are semi- 
oval in shape, measuring about 20 mm. in length. These openings are very small 
for the size of the stomach, but larger openings would tend to weaken its lower 
wall. From one of the openings a gonad is protruding about 50 mm. The 
stomach is circular in shape, forming a large cavity without iftternal septa and without 
distal pouches. From the periphery of the stomach go forth many radial canals. 
The courses of several of the canals were traced by dissection. They pass through 
the layer of jelly and come to the surface of the sub-umbrella. It has already been 
stated that the Medusa is of a dark reddish-brown colour, which is an opaque surface 
layer confined to a very thin skin, which can be peeled off from the underlying jelly 
This skin, at first, was mistaken for the ectoderm, but after further investigation and 
consideration, it seems more likely to be an artificial product, formed after preservation 
On tracing the radial canals from the stomach it was found that they came to the 
surface of the sub-umbrella near the periphery of the stomach, and that their open 
ends were covered by the reddish skin. There is not the slightest trace of a canal 
system over the surface of the sub-umbrella, nor of any muscles. One would naturally 
expect to see powerful circular muscles on the sub-umbrella, considering the size of 
and thickness of the umbrella, and the great length of the oral arms. I believe that 
all the circular muscles, and the whole of the canal system on the sub-umbrella, have 
peeled off. Their absence would account for the abrupt termination of the radial 
canals after passing through the wall of the stomach. 
The margin of the umbrella is very much damaged and broken, but there are 
indications, here and there, of lobes, which are, perhaps, the basal portions of larger 
lobes. There is not the slightest trace of a tentacle, nor of a sense organ. Except 
for the gonads the specimen is but little more than a gelatinous skeleton. 
The presence of a central mouth, and oral arms without internal canals excludes 
this Medusa from the Rhizostomata. It, no doubt, belongs to the Semeostomata. 
The absence of marginal gastric pouches, and the presence of radial canals, indicate 
that it belongs to the Ulmaride. It is best to place this large Medusa provisionally 
in the genus Diplulmaris, as it is too imperfect to justify the possession of a new 
generic name. 
