04 Mr. E. S. Russell on Depastrum cyatliiforme. 



up the beach. In its natural conditions it is almost always 

 pendent, being incapable of supporting itself with static 

 extended and erect, on the upperside of a stone. When 

 watched carefully in confinement it is seen to turn the widelv 

 expanded bell-like umbrella in different directions, as if 

 searching for food. It appears to be quite incapable of 

 refixing itself after having been dislodged from its resting- 

 place. 



The stalk is very contractile, as is also the rim of the 

 umbrella. Four muscles, which extend up the tamioles 

 (PI. V., tm.), are the agents for contracting the stalk, while 

 the margin is contracted by a circular muscle (cm.) which 

 passes round outside the insertion of the tentacles, and in 

 contracting pulls the margin well over the tentacles, leaving 

 only a hole in the centre, through which the tips of some of 

 the tentacles appear. I may here remark that it is only in 

 partly contracted individuals that several rows of tentacles are 

 seen ; in fully expanded adult individuals there do not appear 

 to be more than two rows. Haeckel, in his diagnosis of this 

 species (' System der Medusen '), describes it as having the 

 tentacles in several rows. Furthermore, none of my specimens 

 reach the dimensions noted by Haeckel (8-10 mm. for 

 length of stalk, length of umbrella, and breadth of umbrella), 

 the largest I have seen having a stalk only 7 mm. long, 

 while the usual size of good-sized specimens is 4 mm. for 

 length of stalk, 6 mm. for height of bell, and 5-6 mm. for 

 breadth of same. These specimens seemed mature, having 

 well-developed gonads. 



There appear to be two forms of the species among my 

 specimens — one as figured, the other with a much sharper 

 distinction between stalk and umbrella, and with the breadth 

 of the umbrella as great as, or even greater than, the height 

 of the umbrella. This latter seems to be the typical form, 

 for Haeckel describes the umbrella as being almost as high as 

 broad. The measurements of a medium-sized individual of 

 this latter form are: — Length of stalk 3 mm.; height of 

 umbrella 4 mm ; breadth of umbrella 4*8 mm. The smallest 

 specimen I possess measures respectively 1 mm., 1*1 mm., 

 and 1*4 mm. 



The sexes are distinct, but, so far as I can make out, indis- 

 tinguishable in external appearance. The gonads are typically 

 in four double rows, but I have a specimen with only three 

 gonads and three lobes to the manubrium. Indeed, the 

 animal is very variable, especially as regards the number of 

 fascicles of secondary tentacles. The ova and spermatozoa 

 are very minute and very numerous. I attempted rive times 



