194 THE MEDUSAE. 



diameter, and has forty-six tentacles. The smallest is about 2 mm. high, 

 with thirty-three tentacles. 



The bell is high ; its apex flattened ; the gelatinous substance thin. 



The tentacles are solid, about as long as the bell height ; coiled spirally 

 when contracted. They have swollen bases, each of which bears an ocellus 

 on its inner (velar) side. 



The manubrium is highly contractile ; it does not extend to the bell- 

 opening. After preservation it presents the condition represented in PI. 44, 

 fig. 12. The mouth arms are more simple than they are described for 

 any adult species except L. horealis, being very short, and each branching 

 only twice, so that at each corner of the mouth there are four nettle knobs 

 (sixteen in all). The peduncle of chordate cells, so well described by Brooks 

 and Rittenhouse, is short (PI. 40, fig. 3), and in preserved specimens almost 

 entirely masked by the contraction of the manubrium. 



Gonads. — The gonads are interradial, and entirely discontinuous in the 

 perradii (PI. 44, fig. 12). They are oval and prominent. 



Color. — The gonads are pink, tentacle bulbs reddish, ocelli black (PI, 

 40, figs. 3, I^). 



The specimens closely resemble Mayer's (:04) account of i. alexandri 

 except that the branching of the labial tentacles is less complex, there being 

 only four instead of eight knob-like terminations to each ; but the fact that 

 there are many small marginal tentacles among the larger ones suggests 

 that specimens have not yet reached the final stage in their development so 

 that further development of labial tentacles might be expected. 



The specimen figured by Brooks and Rittenhouse presents an even sim- 

 pler condition of the mouth arms, which are simply bifid. Inasmuch as 

 Mayer has found that the branching of these organs increases in complexity 

 with growth, we may assume that the three conditions represent as many 

 stages in development, rather than specific differences. In all the bell is 

 high and flattened, manubrium short, and the peduncle much reduced. 



In L. ocellata Agassiz and Mayer (: 02), from the Paumotus Islands, the 

 gelatinous peduncle is longer, the basal dilations of the radial canals being so 

 prominent as to more nearly resemble the condition in Turritopsis. The 

 labial arms likewise are more highly developed, the branching progressing 

 even further, and the arms themselves being long and tentacular instead 

 of mere nematocyst knobs. Furthermore, the tentacles in this species are 

 described as short and stiff. It is possible that these differences are to be 



