\ha = 0.12 mm. 



502 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Measurements. — Aperture] , 



* [la = 0.10-0.12 mm. 



Affinities. — This species is very well characterized by its large 

 tuberosities. It differs from Flabellopora lenticularis in its elongated 

 colonies (and nondiscoidal), in its larger oral dimensions and in the 

 presence of exterior areas. 



As in Flabellopora elegans and in F. arcultfera the orifice of the 

 avicularia is not on the plane of the aperture; it is arranged on a 

 plane almost perpendicular. 



Biology. — The geographic distribution of this species is rather large 

 in the interior of the Philippines but it has not been noted on the 

 oceanic borders. 

 Occurrence. — 



D. 5147. Sulade Island, Sulu Archipelago; 5° 41' 40" N.; 120° 



47' 10" E.; 21 fathoms; co. S., Sh. 

 D. 5213. Destacado Island, east of Masbate Island; 12° 15' N.;. 



120° 57' 30" E.; 80 fathoms; S. M., Sh. 

 D. 5217. Anima Sola Island; 13° 20' N.; 123° 14' 15" E.; 105 



fathoms; crs. gy. S.; 17.2° C. 

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

 119° 09' 52" E.; 175 fathoms; fine S., Co. 

 Cotypes — Cat. Nos. 8305, 8306, U.S.N.M. 



FLABELLOPORA IRREGULARIS, new species 



Plate 72, figs. 1-11 



Description. — The zoarium is free, irregular either of narrow lamel- 

 lae or broad fronds; the length varies from 5 to 15 mm.; the angle 

 of the initial base is larger than the terminal angle. The walls of the 

 zooecia are ornamented with granules separated by pores and avicu- 

 laria of which one is in the immediate vicinity of the aperture; the 

 avicularia are large, orbicular or elliptical with pivot, with beak of 

 variable direction. The aperture is orbicular or oval; the distal 

 sinus is wide, shallow, semielliptical; the peristome is thin and little 

 salient; the proximal pore is large and placed on the peristome. 



Measurements. — Aperture], 



r [Za = 0.11 mm. 



Variations. — The variations are not solely zoarial; the exterior 

 ornamentations are also very irregular. The granules disappear with 

 abrasion or age. The peristome is generally thick but it is thin on 

 the little calcified specimens. The vigorous specimens have a salient 

 cushion around the apertures. Finally the latter are often very deep 

 and arranged at the bottom of a sort of funnel. 



On the large colonies the zooecia of the initial portion are not 

 directed in the same way as the others. 



