178 THE MEDUSAE. 



Otocysts. — These are very numerous, but they are so crowded among 

 the tentacles that it is impossible to count them. Double examples are 

 often seen (PI. 35. fig. 5). 



Gastrovascular system. — The stomach in the large specimen is about 

 30 mm. in breadth, i. e. one half the diameter of the bell, and unchanged 

 in its preserved state from the condition seen while alive. The lower 

 gastric wall is well developed, far from rudimentary ; but the mouth never- 

 theless is widely open, although the gastric wall shows no sign of contrac- 

 tion. In view, however, of my observations on .4. macrodactylum, I hesitate 

 to assume that it may not be much more extensible than it appears to be. 

 There are thirty-one lips or oral prominences, about one third as many 

 as there are canals. They are rather smaller than Brandt has figured 

 them (PI. 35, fig. 4), but the difference is not greater than might easily be 

 caused by slight contraction. 



Canals. — In the large specimen there are ninety-four canals, which are 

 as obviously of different generations as are the tentacles. Many of them 

 are stout, and others very slender ; but there is no definite arrangement of 

 different sizes. The irregular arrangement is clearly seen in the photograph 

 (PI. 35, fig. 4). One of the canals is dichotomously branched near its base; 

 all the others are simple. All of the larger canals bear gonads (which seem 

 to be mostly emptied of their contents), but many of the more slender ones 

 are sterile. This difference was noted by Mertens ; but the two kinds of 

 canals are irregularly arranged instead of regularly alternating, as repre- 

 sented (Brandt, '38). In the small specimen there are only forty-seven 

 or forty-eight canals, but they show the same divergence in size as do 

 those of the mature individual. Fourteen of the larger ones already bear 

 gonads ; the remainder, however, are sterile. 



Color. — Both our specimens show the characteristic pigmentation de- 

 scribed by Brandt, the tentacular bulbs being of a very deep bluish black, 

 which now after preservation is black and very opaque. Otherwise the 

 specimens are entirely colorless. 



So far as I can learn, no undoubted record of this species has appeared 

 since its original description in 1838 by Brandt, for although a specimen 

 was recorded by me from the Maldive [slands (: 04, p. 256) under the name 

 I. coeruh cens, its fragmentary condition made positive identification impos- 

 sible. The type specimen was taken by Mertens in the Pacific in about 

 V. and Ml W. 



