158 



formis being restricted to West-Indian seas, whereas all the other 

 species occur in the Malay Archipelago. Probably it would be the 

 better course to separate hydriformis from the other species, which 

 then should be named Chondrocloea. The characters which separate 

 hydriformis from the other species are the presence of rods in the 

 tentacles and the viviparity, but as it is in all other respects very 

 like the other species, and as our knowledge of the systematical 

 value of the mentioned characters is not sufficient as yet, I prefer 

 for the present to refer all the species to the same genus, Syn- 

 aptula (cf. p. 155). 



In the key to the species, some of the species are found in 

 more than one place. This is due to the less satisfactory preserva- 

 tion of some of the species, some of the characters used for se- 

 parating these species being not discernible with certainty. 



Key to the species of Synaptula. 



1. Colour uniformly purple, neither reticulated nor mottled with white 



stripes or spots. Diameter up to 2 cm violacea 



Colour not uniformly purple. (When purple, always more or less 

 reticulated and the diameter not more than half a cm) 2 



2. Colour dark violet with five white stripes (Pl. II fig. 5) ater 



Colour different, not dark violet with five white stripes .... 3 



3. Tentacles 15 (14) 4 



Tentacles 13 (14) 5 



Tentacles 12 (10—13?) 18 



Tentacles 10 (9— 11) 19 



4. Colour dark brown or nearly black, tentacles normally 15, digits not 



united by a web reciprocans 



Colour pale reddish, tentacles probably 14, digits united by a distinct 

 web rosea 



5. Tentacles nearly one third of body-length, gonads unbranched indivisa 

 Tentacles shorter, gonads distinctly branched 6 



6. Miliary granules entirely wanting aspera 



Miliary granules present as rosettes or more or less complete circles 



of minute granules 7 



7. Digits united by a web 8 



Digits not united by a web 15 



8. Anchor-plates nearly oval, in posterior end of body often reduced 



Fig. 22. 14-17 neirensi* 



Anchor-plates neither oval nor reduced in posterior end of body.. . 9 



9. Cartilaginous ring voluminous with small perforations close to the 

 circular canal 10 



