204 THE MEDUSAE. 



of the walls of the manubrium, and is merely the end-stage in the process 

 by which simple interradial gonads are transformed into horseshoe-shaped 

 structures. 



The folding of the gonads is complex, yet more regular and consider- 

 ably more pronounced than Maas has represented it. A typical example is 

 represented in Plate 43, figure 6. 



I have already called attention to the fact that the tentacular bases 

 in the present series (PI. 43, fig. ?) are less swollen than Maas ('97) repre- 

 sents them. The number of rudimentary tentacles is important, inasmuch 

 as it may prove to be of some taxonomic value. In the largest speci- 

 mens there are from twenty-five to thirty of these per quadrant, i. e. from 

 one hundred to one hundred and thirty on the entire margin. In life the 

 lips are long, and folded in an extremely complex manner. 



Color. — In life the gonads vary from orange to brownish red ; manu- 

 brium, lips, and radial canals pale lemon yellow ; tentacles yellowish. Since 

 the present specimens agree closely in this respect with those described by 

 Maas ('97) from notes and sketches made from life by Mr. A. Agassiz, it 

 appears that the coloration of this species is fairly constant. 



One of the two localities at which S. divisa was taken, Station 4644, is 

 near the type locality, being just south of the Galapagos Islands. The 

 other locality is close to the Mexican coast, southeast of Acapulco. In the 

 Atlantic, S. pterophylla is recorded from the West Indies, between Cuba and 

 the Bahama Islands (Haeckel, '79), and Dr. A. G. Mayer informs me that 

 he has since taken it himself in the West Indies. 



Tiaridae Haeckel, ls7'.>. 

 sens. em. Vanhoffen ('89). 



Anthomedusae with gonads primarily interradial, though this location 

 may be masked secondarily by growth ; with from four to many hollow ten- 

 tacles; radial canals broad, basally dilated, secondarily uniting with the 

 manubrium, thus forming the so-called mesenteries. 



The following genera of Tiaridae seem sufficiently well established : - 

 Turris, Conis, Tiara, Pandea, Catablema, and Tiarocodon Browne (,: 02). 

 Vanhtiffen ('89), il is tine, has argued that. Pandea, Turris, and Tiara should 

 all be united, the differences between them in the form of the gonads being 

 at i idual, if not largely due to different stages in development; but 



