i62 Records of the Indian Museum. [Vol. III^ iQog-] 



or near the surface, that is to say in a position in which external 

 agencies act most readily on the water and therefore on the or- 

 ganisms which it contains. Anactinia appears to have adopted 

 the former means of progression and to have become modified 

 accordingly, probably in the course of evolution from a Cerianthid 

 ancestor. 



As regards described forms to which Anactinia may be allied, 

 it bears a somewhat close external resemblance to the minute larva 

 described by van Beneden {Les Anthozaires de la '' Plankton- 

 Expedition,'' p. 107, pi. ix, 1898) as Apiactis denticulata, but, apart 

 from other differences, exhibits no trace of the thickening of the 

 mesogloea characteristic of that form. Possibly it is related to the 

 same author's Ovactis {op. cit., p. 56), but there are several impor- 

 tant features wherein it differs from that genus. Both these forms 

 are regarded by van Beneden as larval. 



Considering the doubt which exists as to the maturity of my 

 specimens and the resemblance they bear to some of van Beneden's 

 genera, I think it best not to define the form they represent as the 

 t3^pe of a new family, but the genus and species may be described 

 as follows : — 



Genus Anactinia, nov. 



Pelagic Cerianthidea without tentacles or a protective sheath. 

 The musculature of the column as in the Cerianthidse. Mesen- 

 teries twenty-four or more ; the membranous part of each mesentery 

 strongl}^ developed and forming in cross-section a protrusion direc- 

 ted away from the ciliated groove. Acontia but no (?) cinclides 

 present. Column conical when full}' expanded, the aboral pole being 

 pointed. The external surface smooth, feebly ciliated. Ectoderm 

 richly armed with large nematoc^'sts at every point. The ciliated 

 groove of great extent relative to the stomodseum. The mesen- 

 teries at both ends of the stomodaeum ver}^ short. No foramina 

 in the mesenteries. 



Anactinia pelagica, sp. nov. 



Peristome at right angles to the column when full}^ expanded. 

 Mouth slit-shaped, with the ciliated groove always more or less 

 patent at one end. A microscopic, imperforate tubercle (represent- 

 ing a tentacle) on the external surface above the upper end of each 

 mesenterial interval. Mesenteries 24 or 26. External surface 

 minutely ])licated longitudinall}^ at the aboral end. Colour pale, 

 with a slight vinous tint, which deepens to light brown at the aboral 

 pole ; the external tissues somewhat feebl}' translucent, ha\-ing 

 a milky appearance in life. The basal pore relativel}' large, not 

 provided with a sphincter. 



