564 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Family TRETOCYCLOECIIDAE Canu, 1919 



Genus TRETOCYCLOECIA Canu, 1919 



TBETOCYCLOECIA PARVULA, new species 



Plate 90, figs. 10-13 



Description. — The zoarium is free, simple and turbinate or com- 

 posite and formed of superposed, independent subcolonies forming 

 an ensemble more or less branched and small. The tubes are 

 polygonal, without peristome and with little thickened walls. The 

 ovicell is elliptical, flat, smooth, perforated by a small number of 

 tubes. 



Affinities. — This is a very curious species. The penduncle of the 

 simple zoaria is very long; sometimes it is bifurcated and two colonies 

 remain attached to the same base. The celluliferous tops (or 

 capitula) do not touch. In the composite colonies each subcolony 

 grows laterally from the top or head of the inferior subcolony. The 

 tops do not have a well determined form and are irregularly orbicular 

 or elliptical. The new branches arise from the bifurcation of a 

 peduncle. 



This species is much smaller than Tretocycloecia flabellaris in which 

 the method of gemmation is identical. In the zoarial classification 

 of Gregory this species could be classed in the genus Discofascigera 

 D'Orbigny, 1852, considering only the simple colonies, but there are 

 no genera recent or fossil for the reception of composite dendroid 

 colonies. In our classification it is naturally placed in the family 

 of Tretocycloeciidae. If thin sections reveal the absence of meso- 

 pores which appears possible from the exterior it would be necessary 

 to create a new genus. Unfortunately we have not been able to 

 make such sections. 



Occurrence. — 



D. 5574. Simaluc Island, north of Tawi Tawi; 5° 30' 45" N.; 



120° 07' 57" E.; 340 fathoms. 

 D. 5579. Sibutu Island, Darvel Bay, Borneo; 4° 54' 15" N.; 

 119° 09' 52" E.; 175 fathoms; fine S. co.; 13° C. 



Cotypes.—C&t. No. 8395, U.S.N.M. 



TRETOCYCLOECIA FLABELLARIS, new species 



Plate 91, figs. 1-6 



Description. — The zoarium is free, simple or composite. The 

 simple zoaria are flabelliform with very narrow base; the peduncle 

 is covered by a transversely striated epitheca; the top is long, convex, 

 more or less lobed. The compound colonies arise from the bifurcation 

 of the peduncle which engenders thus an arborescent zoarium. Other 

 branches are formed by the eccentric development of a flabelliform 



