On a new Pseudaxonid Genus — Dendrogorgia. 67 



Gorgonellidae. The axis is markedly " sclerogorgic " in that it consists of 

 individual spicules, different from those in the ccenenchyma, embedded in a 

 horny matrix. The horny substance, in which the spicules lie longitudinally, 

 is deposited in the form of concentric laminse, but the same applies to the 

 genus Suberogorgia, as was pointed out by Gray in his original description of 

 this genus, where he says : — -" Axis, pale brown, formed of rather loosely 

 concentric fibrous laminae, containing a large quantity of calcareous matter." 



The proportion of the horny material to the calcareous is, however, very 

 much greater in the present case than in Suberogorgia ; the nature of the 

 colony is quite different; there is no trace of two main longitudinal canals 

 larger than the others in the present specimen, and the spicules are very 

 distinctive, both those of the axis and those of the ccenenchyma. 



For these reasons it seems necessary to establish a new genus, which 

 we propose to call Dendrogorgia, in the Family Sclerogorgidse, Order 

 Pseudaxonia. 



The following generic diagnosis, based however on a single species, 

 may be given : — 



Colony very robust, slightly branched approximately in one plane ; the 

 branching is a false dichotomy. The axis is " sclerogorgic," and is moderately 

 soft; it does not contain solenia, and is composed of concentric laminae, 

 consisting of a horny matrix in which spicules are embedded longitudinally. 



The spicules of the axis are smooth or warty, and very irregular in 

 shape. The ccenenchyma is very thick, and is almost of a uniform thickness 

 throughout. It is densely packed with small spicules which are pre- 

 dominately triple-star-shaped ; double-stars also occur. The triple-stars are 

 of two kinds — (1) those with short " shafts " and large, closely tuberculated 

 " heads," and (2) those with long " shafts " and openly-warted " heads." 

 The canal system is very definite; it consists of (1) an inner longitudinal 

 series separating the axis from the ccenenchyma, and (2) an outer longitudinal 

 series which is situated near the periphery. Uniting these there is a dense 

 network of small transverse solenia. The polyps are disposed over the 

 whole ccenenchyma ; there is no distinct separation into verruca 3 , and 

 anthocodite; they are capable of being completely retracted into the 

 ccenenchyma when a small pore surrounded by an octoradiate structure 

 is to be seen. 



Locality. — Bird Island, E. by N. \ N., 5 miles (Cape Colony); depth, 

 40 fathoms ; bottom — mud. 



{Issued separately, 19</t February 1910.) 



