BRYOZOA OF THE PHILIPPINE REGION 379 



Genus ADEONELLA (Busk, 1884) Waters, 1888 



ADEONELLA MINUTIPORA, new species 



Plate 51, figs. 1-13 



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

 dichotomous, broad, ornamented with lateral lobes more or less devel- 

 oped. The zooecia are distinct, separated by a deep furrow, fusi- 

 form, surrounded by a line of small parietal dietellae. The frontal 

 is convex, irregular; it bears a large spiramen in the vicinity of the 

 apertura, a frontal avicularium with very salient beak and a small 

 avicularium in the vicinity of the apertura and the spiramen. The 

 marginal zooecia are provided with a tremocyst but are deprived of 

 the large avicularium. The peristomice is small and transverse. At 

 the bifurcations there are large interzooecial avicularia where the 

 zooecia have tremopores. 



,, -r, . , (hp -=0.06 mm. 



Measurements. — Peristomice ' n nn 



[lp -=0.08 mm. 



Variations. — The young zooecia do not have a spiramen but their 

 apertura bears a rimule for the entrance of the compensatrix. In the 

 superior part of the fronds the frontal avicularium has its very salient 

 beak directed towards the base while the small oral avicularium has its 

 beak turned towards the top. In the inferior part of the basal fronds 

 the frontal avicularium no longer exists. It is replaced by an avicu- 

 larium placed on the line of the lateral pores and in which the beak 

 is turned towards the top. 



On many of the zooecia, principally in the young colonies, there 

 are two small oral avicularia arranged symmetrically on each side of 

 the spiramen. 



On the edge of the fronds the zooecia are transformed in large 

 spatulated avicularia analogous to those which are arranged sporadic- 

 ally on the surface. 



On the living colonies the calcite is white or light brown; it is 

 covered by a brown ectocyst, which makes it very difficult to study 

 this species. The operculum is thin and semicircular. The base is 

 circular and little spread out. 



Biology. — This species is very common in the Philippines. Its 

 geographic distribution is very large. To the west it passes around 

 Borneo and penetrates into the China Sea which it entirely traverses 

 as we have found it in the vicinity of Hong Kong. To the east it 

 penetrates the Strait of Surigao and then becomes diffused in the 

 Pacific. In latitude it lives from parallels 5 to 21. Space does not 

 exist for the bryozoa for although the colonics are immovable on the 

 substratum, some hours of freedom of the larva is sufficient to diffuse 

 the species across the oceans. 



