TUBULARIA SOLITARIA. 93 



gonophore, but I have not found a mouth or oral tentacles 

 developed in any of the specimens. In fig-. 24 the part of the 

 actiuula next to the manubrium will probably be the portion 

 which will elongate and form the hydrocaulns ; the opposite 

 pole would then be the future oral pole. 



(5) Systematic position. — The present species is some- 

 what intermediate in its characters between the genera 

 Corymorplia and Tubularia, but the occurrence of an 

 actinula seems sufficient to place it in the genus Tubularia. 



It agrees with Corymorplia in the following characters : 



(1) Solitai'y hydrocaulns. 



(2) The softness of the perisarc. 



(3) The base of hydranth occupied by differentiated layers 

 of endoderm. 



(4) The arrangement of the endodermal canals approaches 

 the condition seen in Corymorplia rather than in Tubularia, 



It agrees with Tubularia in the following: 



(1) Occurrence of an actinula. 



(2) No papilliform or filamentai-y appendages at the 

 proximal end of hydrocaulns. 



(3) The comparative fewness of the oral or distal tentacles — 

 sixteen to twenty-one instead of about eighty, as in Cory- 

 morplia. 



(4) Pendulous endodermal lobes hanging down from 

 hypostome. 



(5) The number of basal or proximal tentacles — sixteen to 

 twenty-one. 



(6) The shape of the nematocysts. 



On the w'hole it may be considered that in the trophosome 

 it is closely related with Corymorplia, and in the gonosome 

 with Tubularia ; however, the presence of an actinula is 

 so characteristic of Tubularia that I have considered it 

 advisable not to found a new genus for the reception of the 

 present species. 



