SECONDARY BELL-TENTACLES. 19 



carrying it backwards.* The bell then 

 resumes its original form and the process is 

 repeated. 



** Bell " and mouth tentacles armed 

 with dart- sacks. To complete the 



description of the fully-developed free bud. 

 Tentacles are sometimes formed around the 

 mouth and also from the margin of the bell, 

 from which they hang as long streamers, and 

 are armed with powerful batteries of 

 dart-sacks. 



Secondary tentacles. In a few species 

 which have not the bell fully developed and 

 therefore are not so well fitted for swimming, 

 the bell-tentacles throw out near their ends 

 secondary tentacles, and these they use with 

 which to walk as on stilts. Sometimes suckers 

 are formed at their ends. 



Organs for seeing. At the base of the 

 bell-tentacles are little granular masses of 

 pigment, generally of an orange colour, in 

 some cases a crystalline body is embedded in 



• Amongst the Molluscs, the Cuttle fish aud others of its 

 kind, progress after the same manner, and in a backward 

 direction, by the sudden expulsion of water from a kind of 

 pouch. Some bivalves, also. proi)el themselves by suddenly 

 closing their valves and expelling the water. 



