BELONGING TO THE GENERA FILIGELLA AND ACIS. 13 



in well developed cases, is covered with small rounded warts. They 

 vary in size a great deal, the largest of them being arranged on the 

 median line of the sterile side of branches. They are usually 

 1,5 mm., sometimes 3 mm., in major diameter. 



On a thick branch is preserved a small portion of the 

 cœnenchyma; the spicules here are small, markedly elongate and 

 irregularly directed. 



Beneath the superficial layer of the flattened cœnenchyma 

 scales above described, there are others of small (0.45 mm.), fusiform 

 or club-like shape (PI. II., fig. 20). 



All the spicules are white. 



Locality : The single specimen was collected by Mr. Miya- 

 JIMA in the summer of 1898 on the coral ground off the Province 

 of Satsuma. 



So far as I am aware, the following are all the species that 

 have hitherto been described as belonging to the genus Acis : 



1 Acis gaudahqjensis Duch. & Mich. 1860 



2 Acis nutans Duch. & Mich. 1864 



3 Acis solitaria Pourt. 1868 



4 Acis orientalis Kidl. 1882 



(.4. 0. Thoms. ct Hend. 1905) 

 {A. sp. HiCKsoN. 1905) 



5 Acis pustulata Wr. & St. 1889 



6 Acis alba Thoms. ä Hend. 1905 



7 Acis indica Thoms. & Hend. 1905 



8 Acis ceylonensis Tho3IS. &. Hend. 1905 



{A. c. var. inihricata Thoms. & Hend. 1905) 



9 Acis spinosa Thoms. ct Hend. 1906 



