BRYOZOA OF THE PHILIPPINE REGION 167 



and have a simple, semi-elliptical operculum, ending in a straight 



proximal margin. The stem-internodes have a small depressed 



eryptocyst with one pore at the bottom; and excepting the partitions 



of the stolon the other individual forms have their inner cavity divided 



into a series of segments (generally four), separated by more or less 



sharp constrictions. The distal walls have a single pore septula. No 



oviccll and no avicularia. (Levinsen, 1909.) A single genus, 



CKlidonia. 



Genus CHLIDONIA Lamouroux, 1824 



Description. — Same as above for family. 



Genotype. — Chlidonia (Eucratea) cordieri Audouin, 1826. Recent. 



Family ALYSIDIIDAE Levinsen, 1909 



The jointed colonies, springing from a stolonate network, consist of 

 zooecia and gonozooecia. The zooecia, the distal half of which has a 

 depressed eryptocyst, are furnished with a simple opercular valve and 

 with two opesiulae. Valved ovicell. No avicularia. The gemma- 

 tion is lateral. 



Three genera, Alysidium, Busk, 1852, Catenariopsis Maplestone, 

 1899, and Catenicula O'Donoghue, 1924. 



of a main branch with some of the adjacent zooecia, X75. H. The forked distal 

 internode of the stem, X75. I. A portion of the stolonate network with the 

 proximal part of a stem, X75. J. Cylindrical internodes being transformed into 

 zooecia by the development of a cup-shaped expansion (the zooecium in an em- 

 bryo state) from the proximal part of the internode, X 55. K. Cylindrical inter- 

 nodes which apparently are changing into zooecia by a gradual swelling of the 

 internode, X55. L. A cylindrical internode with its cup-shaped proximal expan- 

 sion, from the frontal aspect, X55. M. A transverse section through a zooecium. 

 The thick frontal wall, the small concavity (corresponding with the distal pore 

 in Figure F) and the septula are seen, X75. N. An internode of the stem, lateral 

 view. Bel ween B and C a distal wall with a uniporous septula is seen. The funnel- 

 shaped concavity is in communication through a pore with the interior of the 

 zooecium, X75. O. An internode of the stem, from the frontal surface. The 

 oval funnel-shape concavity with its pore is seen, X72. P. A quite young inter- 

 node of the stem, the walls of which are still very thin. On account of this the 

 extent of the distal wall (dw) is considerable, and the funnel-shaped concavity is 

 not yet developed. In its place is found an oval opening, X76. Q. A young 

 internode of the stem, from the basal aspect. The uniporous septula is seen as 

 also the oval opening, X75. R. A forked cylindrical internode connected with 

 two single ones. Between B and C the distal wall is seen with a uniporous 

 septula, X 100. (A-R. After Levinsen, 1909.) S. Optic section of the skeleton 

 of a zooecium; a, thinness of eryptocyst, (cry); c, general cavity; ect, dorsal 

 ectocyst; eel,' cctocyst proper; h, hypostege; op, operculum, X75. T. Optic 

 section of a basal joint, X 80. (S, T, after Calvet, 1920.) U. Zooecium, showing 

 the position occupied by the polypide and also the small separate chamber from 

 which the next zooecium starts, X85. V. Stalk showing disk to which the paren- 

 chymc is attached, X25. (V. After Waters, 1896.) 



