CUNOCTANTHA OCTONARIA. 53 



very closely resemble the figure given by McCrady ('57, pi. 12, fig. 4) of a 

 half-grown specimen of this species, 6 mm. in diameter. The bell is high, 

 either rounded or somewhat pointed ; the exumbrellar surface smooth. The 

 margin is deeply incised in the radii of the peroniae, so that the latter are 

 comparatively short. Below the point of insertion of each tentacle there 

 is a nematocyst pad. The adult number of otocysts, three per lappet, has 

 already been attained, but the central one in each lappet is still much 

 larger and shows structurally a later stage of development than the two 

 lateral ones (PI. 17, fig. 2). Each otocyst is connected with an otoporp or 

 " auditory clasp," the ones in the centres of the lappets being the longest. 

 These otoporpae form very pronounced ridges on the gelatinous exumbrella, 

 and are undoubtedly what McCrady f57 b ) and Maas (: 05) have described as 

 " fleshy tubercles." They have likewise been observed in this species by 

 Brooks ('86) and Mayer (: 00). McCrady ('57 b ) was correct in supposing 

 that they contained " thread cells." The otocysts themselves are of the 

 usual "Cunina" type ; those furthest developed contain one or two otoliths, 

 and the low prominences of the urticating ring on which they stand bear 

 bristles (PI. 17, fig. 2). In the small specimens 1.5-2 mm. in diameter 

 (PI. 15, fig. 6) there is, as McCrady ('57), Brooks ('86), and Maas (: 05) have 

 noted, only one otocyst per lappet, but this octocyst is already connected 

 with an otoporp. 



The gastric system resembles the figures given by McCrady ('56, '57), and 

 Brooks ('86) for corresponding stages. In the smallest specimen no gastric 

 pockets have yet been formed, although the future appearance of these is 

 already suggested by a slight lobing of the margin of the stomach in the radii 

 of the tentacles (PI. 15, fig. 6'). In a specimen 4 mm. in diameter the pockets are 

 already developed, but are still shallow, and separated by wide septal regions. 

 This is practically the condition found by McCrady ('57, pi. 12, (ig. J,). We 

 know, however, from the studies of Brooks ('86), who was able to follow the 

 development of this species further, that this condition is not the final one, but 

 that in adults the pockets are nearly rectangular, rather longer than broad, 

 and separated only by very narrow, almost linear, septal areas, an observation 

 confirmed by Maas (: 05) for large specimens in the " Siboga " collection. 



None of the specimens as yet show any trace of gonads. 



Color. — The margin of the gastric cavity is brown (PI. 14. fig. 4); this 

 region is described by McCrady as being yellow; evidently, then, the pig- 

 mentation is variable. Otherwise, the medusa is colorless. 



