BRYOZOA OF THE PHILIPPINE REGION 517 



The mere presence of hexagonal bases to the zooecia is not sufficient 

 to characterize a genus and we can state that it is a deceiving char- 

 acter. 



ACTISECOS REGULARIS Canu and Bassler ,1927 



Plate 66, figs. 1-4 



1927. Actisecos regalaris Canu and Bassler, Classification Cheilostomatous 

 Bryozoa, Proc. U. S. National Museum, vol. 69, art. 14, p. 11, pi. 1, 

 fig. 13. 



Description. — The zoarium is orbicular, convex; on the inner face, 

 the hexagonal zooecial bases, a peripheral row of zooecia without 

 peristome and the ovicells are visible. The zooecia are very regu- 

 larly arranged around the membraniporoid ancestrula; they are long, 

 lageniform, tubular, terminated by a very long narrower peristomie; 

 the frontal is a tremocyst with very small pores. The operculum is 

 ogival. The ovicell is globular, salient, placed on the peristomie of 

 the peripheral zooecia, opening widely toward the middle of the 

 peristomie. 



Measurements. — 



~ , [hop = 0.14 mm. n . , JLz = 0.75 mm. 



Operculum, l n 1Q Zooecia peripherals noAm 



r ilop = 0.13 mm. r F U2 = 0.30mm. 



Biology. — These discoidal colonies appear to have been more or less 



floating and arranged so as to escape the sandbanks 



or being engulfed. There is not a single avicula- 



rium, no zoarial apparatus as in Lunularia. The 



currents alone could turn them and cause them 



to float by tangential pressure. FlG - 215— A ctisecos 



The mechanical actions by their constancy are regulans Canu 



, , . i . , . , ... and Bassler, 1927. 



incompatible with the biological irregularities. Operculum, X85 



Thus the very regular colonies can live only in 



running waters and the very regular and symmetrical development 



of the peristomie is the essential condition of equilibrium. This 



species can not then live in calm waters; it only has been dredged 



in the two Straits of Linapacan and Surigao. Our specimens were 



living and in reproduction. 



Occurrence. — 



D. 5335. Linapacan Strait, Observatory Island; 11° 37' 15" N.; 



119° 48' 45" E.; 46 fathoms; S. M. 



D. 5336. Linapacan Strait, Observatory Island; 11° 37' 45" N.; 



119° 46' E.; 46 fathoms; S. M. 



D. 5478. Tacbuc Point, Leyte; 10° 46' 24" N.J 125° 16' 30" 



E.; 57 fathoms; Sh. 



Cotypes.— Cat. No. 8325, U.S.N.M. 



2182—29 34 



A 



