364 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



avicularium in its much smaller micro-metric dimensions and in its 

 ovicell of very different form. 



Biology. — Our specimens were dead. This is a species of slight 

 depths. The zooecia are much smaller than those of Reteporella 

 laxipes and possess adventitious organs. 

 Occurrence. — 



D. 5137. Jolo Light, Jolo; 6° 04' 25" N.; 120° 58' 30" E.; 



20 fathoms; S. Sh. 

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



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

 D. 5151. Sirun Island, Sulu Archipelago; 5° 24' 40" N.; 120° 

 27' 15" E.; 24 fathoms; co. S., Sh. 

 Cotypes— Cut. No. 8467, U.S.N.M. 



RETEPORA (RETEPORELLA) SPINOSISSIMA, new species 



Plate 46, figs. 1-6 



Description. — The zoarium is free, dichotomous; the fronds are 

 short, compressed. The zooecia are distinct, separated by a salient 

 thread, elongated, hexagonal; the frontal is smooth, little convex, 

 often decorated with a small orbicular avicularium. The peristome 

 is complete, salient (especially on young fronds) and adorned with a 

 large number of very small spines. The ovicell is small, convex, 

 opening into the peristomie, decorated with a median pore. The 

 dorsal bears oblique vibices arranged rather regularly on each side of 

 a longitudinal threadlike ridge and outlining irregular lozenge-shaped 

 areas, concave in the direction of the large axis. 



Measurements . — 



7 • |X2-0.45mm. Peristome (diameter) =0.15-0.20 mm. 

 OOeC U2=0.30 mm. 



Affinities. — This species differs from Reteporella clypeata, new 

 species which it resembles in its zooecial and dorsal aspects, in its 

 complete and tubular peristome and in the absence of a proximal 

 pseudorimule to the peristomice. 



Biology. — Our specimens were dead. The one from Simaluc had 

 simply a thicker peristome. 



Occurrence. — 



D. 5179. Romblon Light, Romblon; 12° 38' 15" N.; 122° 12' 

 30" E.; 37 fathoms; hard S.; 24.2° C. (common). 

 D. 5574. Simaluc Island, Tawi Tawi; 5° 30' 45" N.; 120° 07' 

 57" E.; 340 fathoms. 



Cotypes.—C&t. Nos. 8145, 8146, U.S.N.M. 



