510 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



zoarium. It is the smallest species known. It was dredged at 260 

 meters of depth which confirms the idea of the influence of depth on 

 the zoarial size. 



Occurrence.— D. 5135. Jolo Light, Jolo; G° 11' 50" N.; 121° 08' 

 20" E.; 161 fathoms; fine co., S. 



Holotype— Cut. No. 8322, U.S.N.M. 



KEY FOR THE DETERMINATION OF FLABELLOPORA 



The angle of the initial base is larger than the terminal angle. (Colony- 

 elongated) 2 



The angle of the initial base is smaller than the terminal angle. Col- 

 ony flabellate) 8 



The angle of the initial base is clearly equal to the terminal angle. 



(Colony small, discoid) 9 



The aperture is placed in a lozenge-shaped area 3 



The aperture is not placed in an area 5 



A large tuberosity between the areas F. tuberosa. 



No tuberosity 4 



Avicularia elliptical F. elegans (D'Orbigny). 



Avicularia round F. arculifera. 



[Zoarium irregular, little or not flabellate, in lamella or in fronds. 

 5.] F. irregularis. 



Zoarium geometric 6 



JLarge apertures (0.12 by 0.14 mm.) F. acuta. 



I Small aperture (not more than 0.10) 7 



Avicularia tubifer F. tubifera (12). 



Avicularia elliptical F. planata. 



) No asperities between the apertures; large colonies F. transversa. 



[Asperities between the apertures; small colonies F. aspera. 



f Large tuberosity between the apertures. F. lenticularis. 



I No large tuberosity 10 



[ Parietal pores between the apertures and the avicularia E. pisiformis. 



I No parietal pores 11 



JAvicularia long F. acutirostris. 



1 Avicularia short F. pusilla. 



12. Avicularia not tubifer, mamillosities not adjacent. 



F. mamillosa (Maplestone, 1909). 



Fourteen species are known of which one only is from the southern 

 hemisphere. 



Genus ZEUGLOPORA Maplestone, 1909 



"Zoarium bilaminate, lanceolate. Zooecia on both surfaces, 

 immersed, undefined. Thyrostome suborbicular, with a raised semi- 

 elliptical ridge on proximal margin." (Maplestone, 1909.) 



To the above original incomplete description we would add the 

 following: The colony is a Flabellopora in which the oblique rows 

 of the zooecia are not supported on an initial base but on a much 

 larger and more salient zooecium. The aperture is suborbicular; the 

 sinus is distal; the peristome is very much developed in its proximal 

 part and forms a semi-peristomie on which the proximal pore is 



2 



3.1 

 4 



6. 



7 -t: 



8. 



9. 

 10. 

 11. 



