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The proposal of Cutress (5) to eliminate the categories micro- 

 basic and macrobasic amastigophores also is not acceptable. It is 

 true that there frequently is a short thread on many amastigophores, 

 but this thread is apparently sometimes entirely absent. In our elec- 

 tron microscope studies we have failed to find more than a wisp 

 of a thread at the end of the shaft of these nematocysts in Metri- 

 dium and in thin sections we have not been able to verify, as Cutress 

 suggested, that this thread is attached to the inner capsular wall 

 near the end of the shaft. Studies such as Cutress', which were 

 based on the light microscope alone, cannot resolve problems such 

 as this and we must await definitive electron microscope studies. 



The new category of nematocysts, microbasic q-mastigophores, 

 which Cutress described may indeed be a valid type although this 

 too is open to question. I and other workers have noticed dart- 

 like structures which characterize q-mastigophores lying among 

 exploded nematocysts. Weill (10) reports a number of such oc- 

 currences and reviews some older accounts. These darts, which Cut- 

 ress says are unattached discrete structures, occur within the shafts 

 of certain microbasic mastigophores of acontiate anemones. Cutress 

 reports them from the genera Metridiwn and Aiptasia, to which 

 I can add Diadumene. It was my conclusion that the darts in 

 Diadiimenc franciscana were nothing more than the mass of spines 

 which should have armed the shaft. These spines are tightly curled 

 within the shaft as we have seen in electron micrographs (unpub- 

 lished) and are commonly sloughed off soon after eversion of the 

 shaft as many workers have noted. Little would be required for this 

 mass of spines to stick together, lose their contact with the shaft and 

 form the dart. Whether this happens accidentally or as a nonnal 

 process is not known. In Diadumene franciseana the darts could 

 usually be found lying near a mastigophore with no spination on 

 the shaft. Cutress, however, figures darts emerging from mastigo- 

 phores with spined shafts and associated with nematocysts with 

 spined shafts. If these are accurate observations, the recognition of 

 a special nematocyst, the microbasic q-mastigophore, certainly is 

 called for. It is unfortunate that Cutress did not choose some other 

 name than dart for the organized structure contained in his q-masti- 

 gophores. This name, dart, had already been used by Picken (7) 

 to describe the tip of the packed spines as they emerge from the 



