BRYOZOA OF THE PHILIPPINE REGION 



255 



Biology. — Petralia japonica lives at all depths of water from 16 to 

 262 meters. It does not like waters too calm or too warm and we see 

 it descend in depth on approaching the equator; the locality of the 

 deepest, Sibutu, is situated at 4° 54' N. latitude. 

 Occurrence. — 



D. 5311. China Sea, vicinity Hong Kong; 21° 33' N.; 116° 15' 



E.; 88 fathoms; crs. S., Sh. 



D. 5579. Sibutu Island, Darvel Bay, Borneo; 4° 54' 15" N.; 



119° 09' 52" E.; 175 fathoms; fine S. Co.; 13.2° C. 



Geographic distribution. — Sea of Japan : Cobie, 8-50 fathoms (Busk) ; 



Sagamibar, Kadayama, slight depths; Maizuru, 35-40 fathoms (Ort- 



Fig. 105. — Opercula of Petralia and Petraliella, X85 



A-E. Petraliella crassocirca, new species. A. Operculum with wide band, little 

 chitinized. B, C. Two opercula with chitinized bands. D, E. Two variations. 

 F. Petraliella vorax, new species. G. Petralia japonica Busk, 1884. 



mann); island of Enoshima near Yokohoma (Waters). China Sea: 

 Formosa channel, 270 meters (Levinsen). Indian Ocean: Mauritius 

 (Kirkpatrick), Trincomalee (Hincks). Gulf of Manaar (Thornely), 

 Natal (Waters), Wasin, British East Africa, 10 fathoms (Waters). 

 Red Sea: Khor Dongola, off Shukak, 9 fathoms, Bay of Agig Suraza 

 (Waters). 

 Plesiotype. —Cat. No. 7999 U.S.N.M. 



Genus PETRALIELLA Canu and Bassler, 1927 



The ovicell is hyperstomial, never closed by the operculum, buried 

 in the distal zooecium. The shield-like area is very well developed 

 but irregularly around the aperture; it is very often bipartite; it bears 

 almost always two small lateral avicularia; in its proximal portion a 

 large avicularian umbo often appears. Twenty-five tentacles. 



Genotype. — Petraliella (Escharella) bisinuata Smitt, 1872. 



Range. — Miocene — Recent. 



