68 



HYDROIDA II 



tlie apophyses, which is here evident at tlie first glance. In this case, it would scarcely be possible 

 for anyone to doubt tliat the specimen is a young Nemcrfcsia^ the more so since the stem is strikingly 

 thick. Further confirmation is in both instances afforded by the branch apophyses [c and e)\ in both 

 colonies we find the characteristic "mamelou" on the upper side of the apophyse, close to the stem, 

 whicli proves that the>' belong to the Nfniertesia. The entire arrangement of the hydrothecae and 

 sarcothecse also shows that the species is Nc7)iertcsia ramosa. 



The stages found already show that the younger Nemertesia are throughout constructed after 

 the Pluniularia type, with biserial apophyses, and that Scmertesia must be derived from Pliiiinilaria. 

 It would furtlier seem to suggest that Phiiinilaria caulithcca Fewkes is probably a voung stage of a 



200 m. boam. (ooom. 2ooom. 



Fif?. XXXIII. Occurence of Nrmeiiesia raiiwsa in the Northern Atlantic. 

 In the hatched region the literature notes a common occurrence. 



Nemertesia. And il is likely that also other Plunm/aria species in reality cover young Nrmcrfrsia 

 species, and sliould, from the presence of a^ "mamelou", be transferred to that genus. 



Among the synonyms of Nemertesia ramosa should also be reckoned A)itenmilaria variabilis 

 Brocli, The defective specimens, where only the chitinous parts are preserved, have lost all their 

 sarcothecse, so that only a hole in tlie periderm, or a slightly raised part here and there, shows where 

 the sarcothecse have been. The difficulty of discerning these remains has led to their being regarded 

 as variable in number, and the remains or traces of supracalycine sarcothecjE had altogether escaped 

 attention. Otherwise the colonies agree entirely with Nemertesia ramosa, and must thus be referred 

 to that species. 



Nemertesia ramosa has its chief occurrence in the littoral region, especialh- in the middle and 



