BRYOZOA OF THE PHILIPPINE REGION 537 



that it does not seem to be even a generic essential. Why then are 

 the characters which are constant in other species so mingled here? 

 This is one of the biologic mysteries which the bryozoa reveal to us, 

 the existence and discovery of which requires us to change our classi- 

 fication constantly. 



Affinities. — The species differs from Tubigerina rugosa in its larger 

 peristome and in it more closely connected fascicles one with the other. 

 Occurrence. — 



D. 5141. Jolo Light, Jolo; 6° 09' N.; 120° 58' E.; 29 fathoms; 



co. S. 

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

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

 Cotypes.—C&t. Nos. 8364, 8365, U.S.N .M. 



DIAPEROECIA SCALARIA Canu and Bassler, 1922 



Plate 81, figs. 3-7 



1880. Idmonea milneana MacGillivray, Prodromus Zoology Victoria, pi. 68, 



fig. 1. 

 1922. Plalonea scalaria Canu and Bassler, Studies on the cyclostomatous 



Bryozoa, Proc. U. S. National Museum, vol. 61, p. 49, pi. 11, figs. 1-5. 



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

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

 by 0.14; and zoarial width, 1.20. 



History. — MacGillivray, 1880, discovered Idmonea milneana in his 

 material from Port Phillips Head; he identified it correctly but he 

 said that he figured the largest specimen without remarking that it 

 was not similar to the others; his figure is exactly the reproduction of 

 our Diaperoecia scalaria. We arranged this species in Platonea in our 

 studies of 1922 because of the form of the oeciostome but since then 

 we have found several ovicells of the same species in which the 

 oeciostome, completely isolated, is always orthogonal. It is therefore 

 necessary to arrange this species in Diaper oecia. 



Variations. — The tubes are arranged in true salient fascicles, alter- 

 nating on each side of the longitudinal median axis. There are two 

 to four tubes in each fascicle according to the sinuousities of the 

 branches. The branches are sinuous, never rectilinear, ramified, 

 often quite narrow at their base. The base has the Proboscina 

 growth form creeping over shells; the first free branches are sup- 

 ported by columns for the zoarium is expanded and never erect. 



On well preserved, little calcified specimens the tubes are visible 

 and separated by a salient thread. 



The ovicell is generally placed at the bifurcations of the branches, 

 and is convex and finely porous. It is pierced by a variable number 

 of tubes always isolated from each other. The oeciostome is small 

 orthogonal, subcentral. Small incomplete ovicells without oecios- 

 tome are frequent. 



