14 PEOF. P. MARTIN Duncan's eetision of the 



5. Largely fixed wlien young and becoming free ; having spines 

 on tlie sides. 



6. Corallum always fixed. 



Some of the deep-sea species described by Moseley have widely 

 open calices and angular outlines. The Eocene forms ally the 

 genus to Smilotrochus. Vasilium^ Tennison Woods, a genus 

 with one species, appears to be so closely allied to Flabellum that 

 it should be absorbed*. 



Subgenus Blastoteochus, (genus) Milne-Edwards Sf Jules 

 Hainie, Hist. Nat. des Corall. vol. ii. p. 99 (1857). 



Corallum simple and fixed ; calice elliptical ; columella rudi- 

 mentary and produced by trabecules from the septal ends. Septa 

 non-exsert. Epitheca smooth. Soft parts pink and red. Budding 

 occurs at the sides between the calicular margin and the base, 

 and the buds fall ofi" and grow. 



Distribution. — Recent. Philippines. 



The parent seems to be fixed, and probably the buds get fixed 

 after separation. 



The species which have been included in the next genus are 

 rather difficult to classify satisfactorily. 



In 1848 MM. Milne-Edwards and Jules Haime described the 

 genus Rhizotroclius as follows : — The corallum is simple, subpedi- 

 cellated, and adheres by the means of root-like prolongations, 

 which come from the surface of the epitheca and reach down after 

 the fashion of adventitious roots. There is no columella. The 

 septa are broad and not exsert, and they unite with those of the 

 opposite side of the calice by their inner ends. 



The typical species was IRTtizotrochus typus, Ed. & H., from 

 Singapore {op. cit. vol. ii. p. 98). It has a succession of hollow 

 rootlets, an epitheca which permits the costae to be seen under it, 

 and a very deep compressed calice. 



In MJiizotrochus affinis, nobis (Madrep. Deep-Sea, H.M.S. 

 ' Porcupine,' Trans. ZooL Soc. Lond. vol. viii. pt. v. p. 323, 1873), 

 the epitheca comes up to the very margin, is striated and coarse, yet 

 is inseparable from the wall and, indeed, not to be distinguished 

 from it. The radicles are large and are oflshoots of the epitheca. 

 The coral without the radicles is very closely allied to the broad- 

 based, slightly compressed Flahellum rubrum from New Zealand. 



* T. Woods, Proc. Linn, Soc. New South Wales, vol. iii. 1878-79, p. 43. 



