BRYOZOA OF THE PHILIPPINE REGION 157 



Description. — The zoarium encrusts nullipores and fragments of 

 shells. The zooecia are distinct, separated by a thread, elliptical, 

 broad, little elongated; the mural rim is thick, round, salient, grow- 

 ing thin towards the base; the cryptocyst is shallow, convex, some- 

 times carinated, covered with tremopores and with granules. The 

 apertura is small, terminal, semielliptical, transverse; the proximal 

 border is straight and bears two very small lateral indentations; 

 the peristome is salient, thick, decorated with 5 to 8 spines; the 

 operculum is thick and black. The ovicell is very large, globular, 

 smooth, buried in the distal zooecium, surrounded by costules and 

 fringes, closed by the operculum. The ectocyst is light or rose 

 colored. The ancestrula is small. 



Measurements. — 



. \ha = 0.08-0.12 mm. „ . [is = 0.60-0.90 mm. 



Apertura^, _,_ _ , n Zooecia-, _ „_ 



* Ua = 0.16-0.18 mm. [22 = 0.56-0.70 mm. 



Variety crassa new variety (pi. 17, fig. 10). The mural rim and 

 the peristome are thicker; the dimensions are somewhat larger. 



Variety carinifera new variety (pi. 17, fig. 11). The cryptocyst 

 bears a constant carina; the zooecia are generally a little narrower. 



Structure. — The ectocyst is thin, somewhat transparent; the place 

 of the opesiules is marked by two black spots. The opesiules are 

 little apparent; they are visible on specimens prepared with Javelle 

 water and they then have a small, slightly salient peristome. The 

 pigmentation of the ectocyst is rather variable and appears to depend 

 on the color of the neighboring algae. 



The conformation of the ovicell is remarkable. It is formed a 

 long time after the calcification of the distal zooecium probably by 

 the regeneration of an ordinary polypide into an oviferous polypide. 

 The operculum is of great regularity. The polypidian lamella is 

 very small and little visible. 



Affinities.— This fine species differs from Monoporella venusta 

 Eichwald, 1868, in its greater zooecial dimensions, in the presence 

 of granules on the cryptocyst and in having a much smaller vesti- 

 bular arch. It differs from Monoporella nodulifera Hincks, 1881 in 

 the presence of 5 to 8 spines (and not 2 to 4) and in its fringed ovicell. 



It differs from Monoporella carinata Maplestone, 1900, in the 

 broad instead of long zooecia, in the crowded, very numerous tremo- 

 pores and in its noncylindrical zoarium. This species does not 

 have a large geographical distribution, for it is confined to the south- 

 ern part of the Sulu Archipelago. It was in reproduction and the 

 larvae became fixed in the month of February (7-18). 



Occurrence. — 



D. 5137. Jolo Light, Jolo; 6° 04' 25" N.; 120° 58' 30" E.; 20 

 fathoms; S. Sh. (typical form and var. crassa 

 and carinifera). 



