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Genus Birotulata new genus. 



Colony flabellate. Both nodes and internodes traversed by water-vascular canals. The 

 branches are all borne on the nodes. Characteristic spicules double wheels. 

 Type species, Birotulata splcndcns Nutting. 



I. Birotiilata splendcns new species. (Plate X, figs, i, \a, 2; Plate XII, fig. 8). 

 Stat. 258. Tual Anchorage, Kei Islands. 22 meters. Lithothamnion, sand and coral. 



The type was originally a very large colony, but has been broken into many fi-agments. 

 The specimen was flabellate in form and not reticulate and probably originally measured as 

 much as i meter in height. The trunk and main branches are laterally compressed, the former 

 being 2.8 cm. X i-9 cm. in section, and the latter as much as 2.8 cm. X 2.2 cm. in section. 

 The main stem bifurcates 7 cm. from its pro.ximal end into two very unequal branches. The 

 larger of these, after giving off four branchlets, the stubs of which remain, bifurcates into two 

 branchlets which are approximately round in section, the larger one having a diameter of 2 cm. 

 Some of the more distal branchlets are round and others slightly compressed laterally. The 

 branching is in part dichotomous and in part lateral, the former prevailing in the distal parts 

 of the colony, the ultimate branchlets being 1.5 mm. in diameter. The furcations are usually 

 U-shaped rather than Y-shaped. The calyces are on the sides and front of the colony, leaving 

 a bare posterior space, sharply distinguished by its bright chrome yellow color, as if the colony 

 were crudely painted scarlet on front and sides and yellow behind. 



The individual calyces are closely set and have each a broad border of scarlet which 

 gives the red color to the branches. They are almost entirely included and very small, not 

 being over .5 mm. in diameter on the average. Their walls, like the general coenenchyma, are 

 filled with small smooth double-wheels. The polyps are retractile, and bear a collaret which is 

 rather strong and composed of two or three rows of transverse red spindles. Above these a 

 few spindles are arranged en chevron on each tentacle base, and beyond this the spindles 

 are longitudinal. The nodes are not indicated superficially on the main stem and larger branches, 

 and are nowhere so conspicuous as in Melifodes ochracca. The internodes, as well as the nodes, 

 are penetrated by numerous water-vascular canals. 



Spicules. The most conspicuous and numerous forms are the double-wheels charac- 

 teristic of the genus. These are on the surface and also constitute the chief element in the 

 coenenchyma. They look much like two buns pressed together, sometimes unsymmetrically. Some 

 of them have a small nodule at each end in addition to the two wheels. There are also densely 

 tuberculate short stout spindles, and ordinary spindles, mostly from the polyps, and numerous 

 irregular forms which are usually minute. The spicules of the axis are smooth bar-like and 

 needle-like forms. 



Color. The colony is scarlet and chrome yellow, the posterior face of the distal parts 

 of the colony being sharply difterentiated, as if painted with vivid yellow. The yellow shows 



