BAHAMA MEDUS/E. 



21 



The species of ()lin(lia<l;p ai'e few iu number bnf- are widely scattered. 

 Nevertheless the gco-iraphical range of each species is remarkably restricted. 

 It seems probabhs therefore, that they belong to an ancient race that has 

 suffered extinction in the greater part of (he world. 



Tliey exhibit relationships both to the I<]ncopidiT^ and Trachomediisa^,* and 

 are distinguished by the fact that their primitive tentacles bear adhesive 

 disks upon their aboral sides near their distal extremities. These primitive 

 tentacles are retained throughout life, and project from the sides of the 

 bell above the margin. The marginal, or "velar," tentacles are idiylogeuetic- 

 ally recent, and arise tpiite late in ontogeny. 



A study of the ontogeny of Oubaia and Olindias shows that the adhesive 

 disks of their primitive tentacles are formed from modified nematocyst cells 

 which gradually grouj) themselves so as to foBm a cup-shaped or pad-like 

 cluster. 



ANALYSIS OF THE GENEEA OP OLINDIADxT^. 



OENEEA. 

 Gonionemus. 



Vallentinia . 

 Olindias. . . 



TENTACLES. GONADS. CANALS. 



I Of one .sort only. All have I 1 



adhesive disks and ])roject Ribbon-like, folded sinuousl3^ 4 radial canals only. 

 I from sides of bell. 1 [ 



Two sets of tentacles, one 

 set projecting from sides 

 of bell ; other set arising Papilliform. 

 lower down from bell 

 margin. 



" " I Sao-like .... 



" " Papilliform. 



Ollndioldes. 



I 4 radial and numer- 



ous centripetal ca- 



I I nals. 



I 16 radial and numer- 



6. ribboa-like ous centripetal ca- 



Cubaia aphrodite, Mavek. 



Figs. J^S-JfQ, Plate V. 



Mature Medusa: Figs. 45-49. Bell slightly flatter than a hemisphere and 



about 12 mm. in diameter. About eighty tentacles. About twenty of these 



project from the sides of the bell in a zone above the bell-margin, tiieir en- 



todermal axes extending through the gelatinous substance of the bell. These 



tentacles are ringed at regular intervals with about eight nodular swellings 



containing nematocysts. On tlie aboral side near the distal end of each 



* See Goto, 1903 ; Mark Anniversary Volume ; also Perkins, 1903 ; Proc. Acad. Nat. Sci. Phil- 

 adelphia, 1903, p. 750-790. 



