LIRIOPE. Ill 



the distal half of the radial canals. Since in O.phosphorica, in an advanced 

 stage, the gonads occupy nearly the entire length of the canals, it is possible 

 that the extent of these organs may afford another specific character. 



The number of blind centripetal canals increases rather irregularly with 

 growth, as Mayer (: 04) has described for the young stages of O. phospJiorica. 

 The largest number observed in any one quadrant was twelve, in .the entire 

 bell, forty-six. Large specimens have, as a rule, from eight to eleven canals 

 per quadrant. 



Color. — The gonads are reddish brown to brick red. Otherwise the 

 Medusa is colorless. 



An interesting abnormality of this species (PI. 32, fig. 8) has two separate 

 gastric cavities and no less than nine gonads ; of these, four lie on the 

 radial canals, and the other five, which are much smaller, are situated on 

 blind canals which run outward from the gastric cavity. 



Geryonidae Eschscholtz, 1829. 



sens. em. Haeckel, '79. 



Trachomedusae with four or six radial canals ; with blind centripetal 

 canals ; with long gelatinous peduncle ; tentacles in the young, of two kinds ; 

 gonads borne on the subumbrella. 



Two genera are now generally recognized in this family, Liriope with 

 four, and Geryonia with six radial canals. Both of these are represented in 

 the collection. 



Liriope Lesson, 1843. 

 sens. em. Maas, '97. 



Gervonidae with four radial canals. 



I agree with Vanhoffen (: 02'') and Maas (: 05) that of the various char- 

 acters which have been used to separate species in this genus, e.(/. persistence 

 of embryonic tentacles, number of blind canals, form, size, color, and confor- 

 mation of the gonads, all but the last are subject to such great individual 

 variation as well as to such great changes with growth as to be wholly 

 useless. The shape of the gonads, however, seems more reliable, so long 

 as employed with due regard to the various stages through which these 

 organs pass with the progress of development. 



The present collection contains two well-marked forms with regard to 

 the shape of the gonads ; one with these organs primarily triangular, the 



