[47] MEDUSA FROM THE GULF STREAM. 973 



This medusa has a spherical region above which is considered a Hoat, 

 on the under side of which is clustered a number of small bodies re- 

 sembling tentacles. The former region {pycy.) resembles the bell-like 

 body in a medusa; the latter, a clump of tentacles closely massed to- 

 gether, with the form which we might sujjpose they would have if the 

 entrance to the bell cavity were closed by the velum and tentacles de- 

 veloped over its lower floor. The so-called float is spherical, without 

 apical opening or protuberance, smooth on the outer surface, and with- 

 out radial elevations. Diameter from 7 to 10™™. The wall of the float 

 is thin, and in the interior is a second thin-walled sac or float, which is 

 supposed to correspond to the pneumatocyst (pycy.) of Bhizophysa. 

 The inner sac has no opening into the outer, and does not communicate 

 with organs below. It is destitute of appendages. Its cavity {cav. p.) 

 occupies the whole interior of the float. 



The lower floor of the float is formed of the thickened outer walls 

 which bear the so-called tentacles. The thickened region is found to 

 have a cavity withiu (cav. b.) and to be separated by a muscular floor 

 from another cavity (cav. I.) just below the inner air-sac. On the outer 

 walls of this thickened layer (mm.), at the point where it joins the 

 thin walls of the outer layer of the float, there are found spherical 

 bag-like structures (gm.) of unknown function. These bodies recall in 

 appearance the larger float, from which they hang, and suggest the pos- 

 sibility that they are buds from the outer walls. Whether they are 

 new individuals, peculiar zooids, or chance swellings I cannot deter- 

 mine. They are found in both specimens, and so closely resemble the 

 larger float that the supposition that they are new individuals budding 

 from the tliiclieiied region of the bell seems highly probable. The cav- 

 ity of one of them was found filled with bodies resembling those found 

 on the lower floor. 



The whole external surface of the thick walls of the lower hemi- 

 sphere of the medusa is covered with small clusters of bodies which 

 resemble the gonophores in Velella or the sexual clusters of Physalia. 

 These clusters have a small axis, from the sides of which hang, in 

 grape-like clusters, small, spherical, and ovate bodies resembling ten- 

 tacular knobs, fastened by a delicate peduncle to an axis. The appended 

 bodies are of two sizes, large and small ; and, through the walls of the 

 latter, radial structures which arise under the peduncle can be seen. 

 All are snugly approximated to the outer wall of the animal, and, in 

 one instance, a small fragment of what appears to be an Echiuoderm 

 test (a) was firmly grasped by them. No external opening into the cav- 

 ity of the muscular base on which they hang was found, although care- 

 fully searched for, especially at the lower pole of the medusa. In cut- 

 ting open one of the small spherical bodies {gm.) which arise from the 

 side of the medusa I found it filled with a granular mass, which had 

 some resemblance to the botryoidal clusters on the lower hemisphere of 

 the medusa. 



