342 DE. S. J. HICKSON — EEVISION OF THE 



Every jjolype is fully expanded. This is a noteworthy feature in a species with such 

 thin-walled tentacles and polypes. It must be noted that it is highly improbable that 

 in the natural condition the polypes can retract, for there are no spaces in the basal 

 stolon that could contain them. 



Another very remarkable feature of the species is the minuteness of the spicules. 

 They are a great deal smaller than the spicules of any species of Clavularia I have 

 yet examined (Plate L. fig. 15). They are all of one kind, namely, rhombic in shape, 

 with the angles rounded off, and they show a number of extremely minute thorn-like 

 projections. Each spicule measured 0-05 mm. in length and 0-003 mm. in breadth. 



The specimen now in my possession was kindly given to me by Mr. G. C. Bourne, 

 who found it in shallow water on the reefs of Diego Garcia, in the Chargos Archipelago. 



Clavularia eeptans, sp. nov. (Plate XL VII. j 



This species of Clavularia is quite different in habit from any species yet described. 

 The stolon consists of thin strands creeping over pieces of dead branched coral, in 

 many cases stretching across the spaces between the branches, forming bridges on 

 which polypes may arise. The important point about this form of stolon, and one 

 upon which I was inclined to lay special stress, is the extraordinary area over which 

 each colony extends, and the absence of any special point of concentration. When 

 dredging off" the coast of Talisse I often fished up bits of coral, much too large for my 

 collecting-jars, that had this species of Clavularia growing over it in a form that 

 reminded me of a very wide-meshed net. The whole colony grows, in fact, like a 

 Canariensis creeper, clinging to any projecting branch that may be in its vicinity. 



The breadth of the stolons averages 1 mm., the diameter of the contracted polypes 

 2 mm., and the length of the expanded polypes 7 to 10 mm. 



It should be noted here that it is very rarely the case in Clavularia that the 

 diameter of the retracted polype is actually greater than the average breadth of the 

 stolon from M'hich the polype springs. This character, then, is one which helps us to 

 distinguish Clavularia reptans from other species of the genus. 



The tentacles of this species are rather short and provided with numerous densely 

 packed pinnae, resembling somewhat the tentacles of Clavularia garcice. Spicules 

 absent. 



Locality. I have only found this species at depths of 5 to 20 fathoms in the Banka 

 Straits, North Celebes. 



Clavularia celebensis, sp. nov. (Plate XLVIII.) 



I have established this species for a small specimen of Clavularia I found off Talisse 

 Island in 10 fathoms of water on an old water-worn branch of a madrepore. 



In habit it is very similar to Clavularia viridis, but differs from it in several 

 important points of structure. 



