34 Coelenterata. 



the mesenteries have fused together thus subdividing the coelenteron into 8 longi- 

 tudinal canals. The retractile parts of the polyps contain isolated sclerites but 

 in the other parts the sclerites have fused to form a thick skeletal membrane. 

 A similar form of skeleton is present in the partition walls of the coelentera 

 of the stem and the 8 radially arranged skeletal lamellaj meet in the centre 

 of each ccelenteron to form a skeletal pillar a structure new to Alcyonaria, 

 but postulated by Studer in his (very questionable) derivation of the Gorgonidse 

 (Axifera) from the Telestidse. The firm skeleton in the partitions above described 

 is continued above into the 4 dorsal mesenteries of the free part of the polyp, 

 this is the first time a firm skeleton has been recorded in the mesenteries of 

 an Alcyonarian. P. shows a close similarity to the fossil Auloporidse, especially 

 to Cladochomts, but this is due to convergence. 



Roulef 1 ) records in Ehopalonella n. g. which is near Thouarella, the presence 

 of spines on the horny axis. The spines near the base of the axis are short 

 and massive but others, more numerous and elongate, are prolonged at their 

 tips into a flexible filiform appendage which becomes longer as one ascends the 

 stem of the colony until, by a series of gradations, the first slender polypiferous 

 branches are reached. The spines of Antipatharians are homologous with those 

 of Eh. and are therefore, morphologically, aborted branches. 



Roule( 2 ) refers to Pachyclavularia n. erecta n., in which the colonies, instead 

 of forming a spreading growth, are erect, by virtue of the great thickness of 

 the mesogloea of the basilar membranes. The new Virgularid Svavopsis n. 

 elegans n. connects the two principal colonial types of Pennatulids, namely, the 

 Penninse, which exhibit a clear bilateral symmetry accompanied by a repetition 

 of homologous parts (the leaves) and the Juncinse in which bilateral symmetry 

 is feebly marked or absent. From the latter to the former there are transitions 

 Kophobelemnonidse, Anthoptilidse, Stephanoptilidse, Funiculinidae and finally Virgu- 

 laridse, in which the beginning of polypiferous leaves is seen. S. is a Virgularid 

 without leaves, being in this respect on a level with the Funiculinidye. The 

 passage from radial to bilateral symmetry, with repetition of homologous parts, 

 is important in connection with the estimation of the probable causes of bi- 

 lateral symmetry and of metameric arrangement. 



Thomson records a large specimen (34 inches high) of Primnoa reseda from 

 the Fseroe Channel at a depth of 355 metres. It was salmon-pink in life 

 and viviparous, hollow, diploblastic planulse being present in the coelentera. 



Hickson( 1 ) records Clavularia 1, Alcyonium 1, Ceratoisis (Primnoisis) 3 (2 n.), 

 Thouarella 1, Primnoella In., and Umbellula 1 from the Antarctic. Prim- 

 noisis should be merged with Cer. ; G. spicata n. connects these two genera. 

 Primnoella divergens n. exhibits many characters of Caligorgia and may be 

 regarded as a connecting link between these two genera. 



Gravierf 1 ) describes Mesobelemnon n. gracile n., dredged from coarse sand 

 in the gulf of Tadjourah (Somaliland). M. differs from Kophobelemnon and 

 Sclerobelemnon in the form of its spicules, the very short pinnules on the 

 tentacles and the small number of siphonozooids, which are, however, individually 

 well developed. These 3 genera form a homogeneous group characterised by 

 the polyps inserted on the whole of the rachis (except for a median ventral 

 band) and by the distribution of the siphonozooids on the two faces and on 

 the sides of the polypiferous region. - - See also Gravier( 5 , 9 ). According to 

 Gravier( 6 ) K., S. and M. form a homogeneous group distinct from that com- 

 prising Bathyptilum, Thesioides, Scleroptilum, Protocaulon and Deutocaulon\ it 

 would be better to separate the latter as a distinct family. 



