REPORT ON THE ALCYONARIA. 269 



The buds of axial aud accessory polyps always arise near the tentacular portion of the 

 axial polyps, not from the oesophageal portion (fig. 4). At a distance slightly less than 

 1 mm. below the origin of the tentacles, the first buds appear as warty protuberances, 

 including protrusions of the three body-layers, which enclose a minute lacunar space 

 formed from the expansion of an endodermic canal. Close under these, buds occur 

 in which the still closed oesophageal tube is invaginated from the apex of the wart into 

 the endodermic lacuna to form the future gastral cavity of the polyps. On the margin of 

 the invagination the tentacles are being dilierentiated. The buds below those above 

 described already appear more cylindrical in form, and exhibit in their essential features 

 the different parts of the adult polyps. 



Of interest in relation to the development of the whole is a very young colony only 

 27 mm. in height. Here one can distinguish (fig. 2) an ascending stem beset with 

 spirally disposed polyps. The stem is a simple tubular polyp, which exhibits a row of 

 tentacles at its extremity. The lateral polj^s are likewise cylindrical, and some already 

 exhibit small buds below their tentacles. The whole has exactly the structure of the upper 

 end of an adult axial polyp. The lateral polyps are seen in the act of transformation into 

 axial polyps of the second order. 



The spicules are distributed through the entire mesoderm of the colony, and are 

 continued from the stem and branches into the polyps, where they are developed on to 

 the very tips of the tentacles. 



They consist typically of straight or curved spindles, which are beset with ii-regularly 

 scattered spinose warts. In the deeper mesodermic layers of the axial pol}^s these warts 

 frequently develop into jagged processes, and the spicule thickens at one end into an 

 approximately club-like form. The dimensions of the spicules in length and breadth are 

 0-37 to 0-033 ; 0-225 to 0-025 ; 0-3 to 0-032 ; 0-16 to 0-016 ; 0-12 to 0:012 mm. 



They are generally disposed in longitudinal strands, and form several strata one above 

 the other. In the axial polyps they form a compact layer round about the gastral cavities, 

 and thus represent a sort of axis. 



The colour of the colony when dried or preserved in spirit is white. In the living 

 state they possess, according to Dr. C. Keller, a light chocolate colour with a tint of red. 

 The colour is very quickly lost in spirit. 



From the above it is evident that Ccelogorgia has much in common with the subgenus 

 Carijoa, to which the genus is doubtless allied. The principal differences are, the more 

 emphasised differentiation between the axial and lateral polyps, the absence of horny 

 substance in the mesoderm, and the non-retractile character of the polyps. 



Habitat. — Zanzibar (Rousseau). 



Nossi Be in the Mozambique Channel; depth, 10 to 12 metres (Dr. C. Keller). 



