Art, I. — On the Anatomy of an Arenaceous Polyzooii. 

 By Arthuu Dendy, M. Sc, F.L.S. 



Demonstrator and Assistant Lecturer in Biology in tlie University of 

 Melbourne. 



[Keail May 10, 1888,] 



During the last Easter vacation I was enabled, through 

 the kindness and hospitality of Mr. J. Bracebridge Wilson, 

 to accompany him on several occasions while engaged in 

 dredging operations at various localities near Port Phillip 

 Heads. On one of these occasions we obtained a consider- 

 able quantity of a very remarkable arenaceous organism 

 attached to the base of a mass of Ascidians. On my i-etnrn 

 to the University I examined my spirit-preserved specimens 

 of this organism with some care, but witliout being able to 

 elucidate its true nature. As it promised to prove of 

 unusual interest I wrote to Mr. Wilson, asking him if he 

 could send me some more specimens in a living condition. 

 In consequence of my request Mr. Wilson devoted a 

 considerable amount of time and trouble to again searching 

 for the organism in question, and succeeded in a few days' 

 time in sending me living specimens, not only of the species 

 which I had previously obtained, but also of another quite 

 distinct species of the same genus. These specimens reached 

 me in excellent condition, and a o-lance at the livino; animal 

 at once proved it to be a Polyzoon of very novel and peculiar 

 form. 



The genus, which is new to science, would appear to be not 

 uncommon in Port Phillip, for Mr. Wilson informs me that 

 he has been familiar with it for many years, and has often 

 dredged it by the handful. He has also kindly suggested 

 that, considering the difficulty experienced in determining- 

 its true character, the generic name Cri/ptosoon would not 

 be inappropriate, a suggestion of which I am very happy to 

 be able to avail myself 



I propose to call the species with which I first became 

 acquainted Gryptozoon ivilsoni, in honour of the well-known 

 discoverer of this and many other new and remarkable 



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