BRYOZOA OF THE PHILIPPINE REGION 549 



are little distinct, hardly convex; the peristome is thin, orbicular, or 

 rectangular. The ovicell is large, convex, wide spread between the 

 fascicles over the whole zoarial width; the oeciostome is elliptical, 

 transverse, provided distally with a sort of raised lip, less wide than 

 a tube, hardly salient, and orthogonal. 



Measurements. — Zooecial diameter, 0.20; width of fascicles, 0.25; 

 distance between fascicles, 0.40; dimensions of oeciostome, 0.26 by 

 0.14, and zoarial width, 1.20 millimeters. 



Variations. — This species is well characterized by its fascicles 

 regularly arranged according to scale and quite close together, and 

 also by the form of its ovicell. We have been rather fortunate in 

 finding many ovicells and to recognize among them some variations. 

 They are enlarged at the bifurcations. The oeciostome is absent or 

 isolated or adjacent to a tube. In the last case the oeciostome is 

 turned toward the bottom, although the orifice placed at the base 

 of the peristomie must be in the habitual position. The form bent 

 back toward the base of the oeciostome appears therefore to be due 

 to the closeness of the distal tube. 



Occurrence. — D. 5151. Sirun Island, Sulu Archipelago; 5° 24' 40" 

 N.; 120° 27' 15" E.; 24 fathoms; co. S., Sh. 



Holotype.—C&t. No. 7376, U.S.N.M. 



Genus MESONEA Canu and Bassler, 1920 



MESONEA SIMPLEX, new species 



Plate 86, figs. 11, 12 



Description. — The zoarium is free, subcylindrical, bifurcated, with 

 short branches; the dorsal is convex, ornamented by numerous 

 oblique sulci of little depth and containing irregularly spaced vacuoles. 

 The tubes are little distinct, very short, not developed up to the 

 zoarial margin, with peristomie almost transverse; the peristome is 

 orbicular and thick. The fascicles are formed by only a single tube. 



Measurements. — Diameter of peristome, 0.10 mm.; distance of 

 fascicles, 0.16; number of tubes to fascicle, 1; width of branches, 

 0.56-0.60. 



Structure. — The general aspect of this species is very characteristic. 

 It is a thick, smooth band arranged on a cylinder and bearing the 

 peristomes laterally. In longitudinal section the frontal band is 

 very thick; the tubes are cylindrical, polygonal a little curved at 

 their extremity with triparictal gemmation; the dorsal is much 

 thickened and pierced by long and recurved vacuoles. (See text fig. 

 221.) 



We were in error in 1920 when we indicated tergopores on the 

 dorsal of the genotype Mesonea radians Lamarck, 1812. The figures 

 published are moreover clearly affirmative in this respect. This 

 2182—29 36 



