BULLETIN 59, UNITED STATES NATIONAL MUSEUM. 63 



FLABELLUM DELUDENS von Marenzeller. 



I'late III, tigs. 5, ha, bh. 



184S. Flahellum lamniatiim Mii.ne Kdwarijs and HaiiMK, Ann. Sci. Nat., 3ieme ser., Zool., IX, 



p. 273 (? Phyllodis laciniatum Philippi, 1841 ). 

 1857. FUilii'Uum laciniatum Milne Edwards and IIaime, Hist. Nat. Corall., II, \k !»l'. 

 1864. Fliibellum lacinintum Segvenza, Corall. Foss, Terz. Messina, Pt. 2, p. 91, pi. .\, figs. 7, ''i. 

 1898. Flabellum laclnialam Alcock, Investigator Deep Sea Madrepor., p. 21, pi. ii, tigs. 4, 4a. 

 1904. FlaheUum iMiiden.i von iMARENZELLER, Steinkorallen Valdivia Exped., p. 269, pi. xvii, (ii.'. 



10 (2 figs.). 



Von Marenzeller proposes a new name for this coral, liecause Philippics oriolnal 

 material i.s too fragmentary for po.sitive identitication. He makes ver}" appropritite 

 remarks on the relations between Flahellum inacaMlrewnl Gray, TJloeijathiM arcticus 

 M. Sars, and FlahMnm (dahastrurn Moseley { = Flabellum goodei Verrill). 



Desmpticm. (\>iised on the Hawaiian specimen.s). — Corallum very thin and fraoilc. 

 with a compressed, clonoate, horizontal or almo.st horizontal base, and a liiohly 

 arched, deeply incised calicular margin. 



A short, rather stout pedicel is persistently present, liy which even the; adnlt 

 corallum seems to have been attached: angle of divergence of the lateral edges con- 

 stantly about 180-, the variation slight. Below the edges are wide, thin, often trans- 

 versely undidated, lamolliform crests which connect with the s(>[)ta lying in the ]iiane 

 of the longer axis of the calice, and are frequently produced below the level of the 

 lower end of the pedicel. The faces of the corallum diverge at an angle between 

 .50^ and 7(>. About halfway up a face the outer portions diverge more rapidly 

 than the medial, causing tlie upper part to be concave. ('ost;e usually correspond 

 to the first and second cycles of septa, but are variable in development, fretjuently 

 strong, wide at the bas(>. acute or flattened along the summits; coarse, sinuous lines 

 of growth often ])resent. 



The lower ends of the calice are approximately on ii le\el with the top of the 

 ])edicel, tlie upper edge; very nmch elevated. The deeply incised character of tlie 

 calicular margin has been noted. The deepest incisions usually occur on the sides 

 of the tertiaries in such a manner that the upper ends of tlx' (juaternaries are carried 

 upward on the lobes bearing llie ends of the ])i'incipal septa, thus isolating (lie ter- 

 tiaries. except those next the ends of the ealices, where the incisions alongside the 

 principal septa in the long axis are very di'ep. Deeper incisions occur in most of 

 the larger specimens on eacii side of each inner t(>rtiary of tlie terminal systi'ms. i. (>., 

 the one nearest the medial .system. This tertiary .seems to project in the l)ottom of a 

 deep .sinus. Between these two sinuses on each face is a median lobe with a coar.sely 

 toothed upper margin. Below each of the.se sinu.ses is another lobe, its lower bound- 

 ary formed by tli(> deep incision near the pi'incipal septum at tlit> end of the calice. 

 The outer margin of this lobe is also coarsely denbite. To sum up these characters, 

 the upper margin of each face is usually trilobed. and tln^ margin of each lobe is 

 coarsely dentate. 



Septa distant, thin, in four cycles, in the larger specimens some members of the 

 fifth. There are usually three sizes, the primaries and secondaries of eipial size, 

 fusing by their inner edges near the ba.se of the corallmu; the tertiaries are nar- 



