Prof. Hickson, On Alcyonaria in the Cambridge Museum 367 



said that the genus had been only imperfectly described. In doing 

 so I did not do justice to the excellent description of Sarcodictyon 

 catenata by Herdman* and I wish to make a sincere although 

 belated apology. The submergence of the genus in Clavularia has 

 unfortunately been accepted by May, Kiikenthal and other writers, 

 but since 1894 I have examined several species of Clavularia and 

 by the kindness of Prof. Herdman several specimens of Sarco- 

 dictyon catenata, and I have come to the conclusion that it is 

 desirable to retain the generic name Sarcodictyon. Sarcodictyon 

 differs from all the species of Clavularia I have examined — except 

 Clavularia dura — in having a stolon protected by hard inflexible 

 walls of fused calcareous spicules and in having long retractile 

 anthocodiae which can be withdrawn into shallow convex cahces 

 situated on the strands of the stolon. The stolon consists of 

 flattened strands about 1-5-2 mm. in width, forming a network 

 shghtly expanded at the nodes and in the places where the zooids 

 are situated. The colour of the stolon seems to be almost in- 

 variably red, pink or yellow. 



Clavidaria dura appears to be a connecting link between the 

 two genera in having hard inflexible walls but differs from Sarco- 

 dictyon in the large conical cahces and in the absence of colour. 



The specimen from Australia is growing on a dead cockle shell 

 about 35 mm. in length and breadth. The stolon is of a pale pink 

 colour and forms a very irregular network of strands with meshes 

 5 or 6 mm. across, and the strands are about 1 mm. in width. As 

 the zooids are all completely retracted it is very difficult to deter- 

 mine the exact distribution of the spicules in the anthocodiae but 

 in these parts of the colonies free spicules can be found up to 

 0-2 mm. in length which have the form of irregular spindles pro- 

 vided with numerous irregular tubercles. The wall of the cahces 

 and of the stolon can be seen to be formed of spicules of the same 

 form which in further growth have become jammed together to 

 form a solid structure. 



On comparing the specimen with specimens from the British 

 sea area I can find no characters to separate it from S. catenata. 

 It is true that the pale pink colour distinguishes it from all the 

 other specimens I have seen ; but as S. catenata is known to vary 

 from red to yellow the colour character is obviously not rehable. 

 There seems to me, therefore, to be no other course to adopt 

 than to name this specimen S. catenata notwithstanding the 

 enormous distance that separates the AustraHan from the British 

 habitat. 



* Roy. Phys. Soc. Edin. vra, 1883, p. 31. 



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