84 ERNEST WAREEN. 



depth in the substance of the sponge by a branching- root or 

 hydrorhiza (figs. 3 and 4). 



Around the mouth is a ring of oral or distal tentacles 

 sixteen to twenty-one in number. These originate in as 

 many prominent ridges which run down the hypostome. It 

 is as if the tentacles spring from the sides of the hypostome 

 and adhere to it, becoming free around the mouth. 



The hydranth is somewhat expanded towards the base, and 

 from this region there arises a single verticil of basal or 

 proximal tentacles about sixteen to twenty-one in number. 



The gonophores arise in small clusters from short semi- 

 erect peduncles, which spring from the body of the hydranth 

 just above the verticil of basal tentacles (fig. 4). In each 

 cluster there are three or four gonophores. 



Both male and female gonophores are produced by the 

 same hydranth ; but as far as I have observed they are 

 invariably formed on distinct peduncles. This fact favours 

 the view of regarding the peduncles as blastostyles which 

 are either male or female. 



The hydrocaulus is covered by a thin, soft perisarc covering, 

 which commences in the perisarc-groove situated just beloAV 

 the attachment of the hydranth (fig. b 'p.g.). As the hydro- 

 caulus elongates the perisarc substance is secreted by the 

 epithelium of the groove. The softness of the perisarc 

 differentiates the present species from the typical tubularia. 



The area of attachment of the hydranth and hydrocaulus 

 is small, and under certain conditions the hydranth appears 

 to become decrepit and withers or drops off. The blind end 

 (fig. 3 a, h) of the hydrocaulus can, without doubt, produce 

 another hydranth. I have not, however, been fortunate 

 enough to find a specimen in which such re-formation of the 

 hydranth was taking place ; but in specimens in which the 

 hydranth is withering it seems certain that the lite of the 

 individual is not drawing to a close, for at the same time it 

 may possess rich supplies of food-material stored up in the 

 hydrorhiza (fig. 4 t). 



The basal end of the hydrocaulus is imbedded in the sponge 



