20 MISS RUTH M. HARRISON ON NEW ALCYONARIA 



in the canal-walls ; in neither could I find spicules resembling those figured by 

 Kiikenthal. It is difficult to see on what grounds these specimens have been considered 

 the same species, and Gray's original diagnosis is so sketchy that it is not possible to 

 determine which form has prior claim to the name S. divaricata. On the other hand, it 

 is probable that there are many instances where new species have been made on 

 insufficient grounds. With this in view, Kiikenthal has considerably reduced the 

 number of described species. Por example, the two ' Challenger ' specimens named by 

 Wright and Studer S. cervicornis and S. rhodosticta respectively, he regards as one and 

 the same species, on the grounds of great similarity in the general plan of growth and in 

 the armature of the polyp. They also agree in the absence of spicules from the canal- 

 walls, although this seems to have escaped his notice. There is, however, a striking 

 difference apparent even to the naked eye on which he scarcely lays sufficient stress ; this 

 is the contrast between the spicules of the barren stem. In S. cervicornis they are long 

 spindles disposed more or less transversely ; in S. rhodosticta they are small, very 

 irregular, thorny, many-rayed structures. The polyp-heads are also different in colour, 

 being purple-red in one and orange-red iu the other. If these differences are not 

 sufficient to outweigh the points of agreement and to justify a separation of the species 

 they are at least worthy of special mention. At all events, the above examples illustrate 

 some of the difficulties to be contended with in the identification of species and show how 

 necessary are co-operation and comparison in a genus of such variability and magnitude. 



The subfamily Siphonogorgiaeeae was made by Kolliker (25), who regarded it as 

 intermediate between the Alcyoniidse and the Goi-goniidse, and in it put the single genus 

 Siphonogorgia. Wright and Studer (57) placed Siphonogorgia, together with Chiro- 

 nephthya, Paranephthya, and Scleronephfhya, in the subfamily Siphonogorgiinae of the 

 family Nephthyidae, distinct from the other subfamily Spongodinoe in the abundant 

 presence of spicules in the canal-walls. Kiikenthal (27) removed the genera Para- 

 nephthya and Scleronephthya to the new genus Paraspongodes in the family Nephthyidse, 

 and raised the subfamily Siphonogorginae to the rank of a family equal to the 

 Nephthyidse as the family Siphonogorgiidae, and in it he placed the genera Siphonogorgia 

 and Chironephthya — the justification for this step being that the Siphonogorgiidoe are 

 intermediate in form between the Nephthyidse and the Gorgoniidse ; and he gives as 

 the diagnostic characters of the family: "Em Stammteil fehlt. Kolonie aus wenig 

 verzweigten cylindrischen Asten bestehend, auf denen die in einen Kelch zuruckziehbaren 

 Polypen sitzen." I do not know what is meant by " Ein Stammteil fehlt." In many 

 of the species there is au obvious stalk figured — for example, Siphonogorgia pendula or 

 Chironephthya dipsacea ; and it is so very easy for the stalk to become broken in the 

 process of dredging that it could hardly be a character of much value. In the present 

 report I follow Kiikenthal in recognizing the family Siphonogorgiidae, with the 

 following characters : — Erect tree-like colonies with stiff, slender, cylindrical branches. 

 Polyps may or may not be retractile. Canal-walls richly filled with spicules. 



The family contains two genera, Siphonogorgia and Chironephthya. 



The original diagnostic characters of the two genera have been shown by Prof. Hick- 

 son (18) to be inconstant, but I believe there is a really reliable distinction in the form 



