Miscellaneous. 261 



but very broad ; it projects horizontally all round to the extent of 

 one third the diameter of the bell. The margin of the bell is 

 smooth and slightly undulating only when contracted more strongly 

 than usual. Eound its periphery gently bulbous swellings mark 

 the origin of sixteen to eighteen tentacles (the number varies 

 perhaps between wider limits), which are of great length and fine- 

 ness and sharply pointed at the tips. In the specimens killed in 

 weak osmio acid and excellently preserved they still measure from 

 6 to 10 millim. The nematocysts are distributed in fine closelj'- 

 packed whorls throughout the entire length, with the exception of 

 the bulbous base. On the ex-umbrellar surface of the base of each 

 tentacle there is found an ocellum, a simple spot of pigment, without 

 retractile body. Nevertheless several pigment-cells take part in its 

 composition. In many tentacles the pigment-spot is circular ; yet in 

 its clear centre no stronger retractile body could be detected ; we 

 merely find a few ordinary epithelial cells surrounded by blackish- 

 brown pigmented cells arranged in the shape of a cross. The ocelli 

 are entirely naked ; other sense-organs, as well as marginal bulbs 

 between the tentacles, are completely wanting. 



The very powerful manubrium, hanging down in the subumbrella 

 and extensible as far as the velum, is shaped like a quadrilateral 

 prism, with four interradial longitudinal grooves, so that a trans- 

 verse section is cruciform, with the arras of the cross bluntly rounded. 

 In accordance with this, its lumen is also cruciform, the arms of the 

 cross having a radial direction and running into the longitudinal 

 ridges of the manubrium. 



Oral lobes are wanting. The four radial longitudinal ridges of 

 the manubrium converge at the end with bluntly rounded tips, and 

 so embrace the oral opening. 



There is a small roundish atrium, prolonged into four radial 

 canals, which, however, do not follow the most direct route to the 

 circumferential canal, but are much coiled, even in the case of the 

 living animal when perfectly at rest. 



If the living animal be examined or slightly magnified it at first 

 appears as though four broad, twisted, enteric pouches arise from 

 the centre of the transparent bell, being distinguished by their 

 yellowish-brown hue, and do not reach the margin of the umbrella. 

 Sections show us that the radial canals, as soon as they leave the 

 atrium, are indeed greatly dilated, so that their ventral wall is seen 

 like a protuberance projecting towards the subumbrella, but that, 

 in addition to this, they are also surrounded on both sides and on 

 the subumbrellar surface by the gonads. These extend from the 

 origin of the canals at the atrium along two thirds of their course, 

 after which the canals become very fine and transparent, and pro- 

 ceed in true radial direction to the circumferential canal, into which 

 they open. It is highly probable therefore that it is only in conse- 

 quence of the powerful development of the gonads in the course of 

 the originally straight radial canals that the latter acquire their 

 twisted form through vigorous growth in a longitudinal direction. 



The sexual products are, as has been mentioned above, not yet 

 perfectly ripe in the specimens which were microscopically examined, 

 yet I found in them a multitude of young ova already of tolerably 



