ON THE STKUCTU15E OF CEEATELLA FUSOA (GRAY). 9 



Ilydroidea aud not to the spouges in which group Dr. Gray had provisionally placed 

 them. At the same time it may perhaps be well to note that the finding of 

 thread-cells in dried specimens with a skeleton in the form of a horny network 

 is not in itself absolute proof of their belonging to the Hydroidea inasmuch as at the 

 present time sponges are known to exist the substance of which is pierced by hydroid 

 growths so that it would be possible to find thread-cells in the dried skeletons of 

 sponges. At the same time Mr. Carter was perfectly right, as events have proved, in 

 removing the Ceratelladae from the Porifera though the subsequent discovery by 

 Mr. Bale of the nature of their soft parts has shown that they cannot be placed, 

 where Mr. Carter put them, in the family Hydractiniidfe. 



The next notice of these forms occurs in the Proceedings of the Linneau Society 

 of New South Wales for 1886 (p. 575) when Mr. Brazier recorded the occurrence of 

 CerateUa fiisca from various localities near Sydney such as Bondi Bay and Coogee. 

 In the Proceedings of the same Society for the year 1888 (p. 745) Mr. Bale for the 

 first time gave some description of the soft parts and showed that the zooids were 

 formed on a very different type from those of the Hydractiniidte. The latter have a 

 single circlet of filiform tentacles surrounding the hypostome whilst those of Ceratella 

 are irregularly distributed over the body and are capitate. Mr. Bale accordingly 

 removed Ceratella from its position amongst the Hydractiniida3 assigned to it by 

 Mr. Carter and placed it in a distinct -family to which he gave the name Ceratellidse. 

 He apparently overlooked the fact that Dr. Gray had already adopted the name of 

 Ceratelladae for the family including his two genera Ceratella and Dehitella, so that 

 this name given in 1868 must now be retained. With a more abundant supply of 

 material I have been enabled to work out the structure in greater detail than was 

 possiljle to Mr. Bale to whom we owe the first description of the soft parts and 

 the determination of the fact that Ceratella belongs to a family distinct from the 

 Hydractiniidye. 



Description of the Structure of Ceratella fusca. 



I have endeavoured so far as possible to give a complete account of the anatomy 

 of both soft aud hard parts the only figures yet published being those of the external 

 form given by Dr. Gray* both of which suffice to clearly identify the genera. 



Skeleton. 



The colonies of Ceratella procured on the New South Wales coast measure from 

 Ij — 5 inches in height and are of a rich brown colour. The largest specimen which 

 I have seen is the one procured by Mr. Gabriel which came from Flinders Island 

 in Bass Straits where it had been washed ashore. The figure given l)y Dr. Gray 



* Loc. cit. 



