BRYOZOA OF THE PHILIPPINE REGION 113 



and occurring fossil and (4) the variety biavicularia with two sym- 

 metrical avicularia, also occurring fossil. The variety intermedia 

 Kirkpatrick, 1890, is a special species of the cervicornis group. 



Typical form. — The avicularium is unilateral. The two lateral 

 spines are very short and often absent. The large branched spine is 

 attached to the base of the avicularium; it is very sporadic and most 

 of the cells are deprived of it. 



The zoarium is very rarely incrusting and is almost always unila- 

 mellar, foliaceous, or tubular. It grows on soft algae. The radicular 

 fibers are attached to small hollow tuberosities on the inferior face. 

 The separation of the cell is never apparent on the cellular face and 

 it is inconstant on the other side. There are two distal spines. 



Variety separata, (pi. 11, figs. 5, 6) — The separation of the cells 

 is visible on the cellular face and the connecting tubes appear on the 

 inferior face. The oral spine is quite rudimentary and the distal 

 spines are absent. 



Biology. — All the chitinous appendages and the ornamentations of 

 this species are very fragile and disappear rapidly, even on old 

 zooecia of a living zoarium. In our specimens we have seen neither 

 ovicells nor ancestrula. No reproduction has occurred in February 

 or in September, the two months when collected. 



The sporadic spines are adaptations to depth or to the oscillation 

 of the algae; they do not exist on specimens of shallow waters. 

 Commensal on the delicate algae this species participates in all the 

 events of the life of the latter. 

 Occurrence. — 



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



fathoms; S. Sh. 

 D. 5145. Jolo Light, Jolo; 6° 04' 30" N.; 120° 59' 30" E.; 23 



fathoms; co. S., Sh. 

 D. 5151. Sirun Island, Tawi Tawi Group, 5° 24' 40" N.J 120° 



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

 D. 5577. Mount Dromedario, Tawi Tawi Group; 5° 20' 36" N.J 



119° 58' 51" E.; 240 fathoms; crs, S.; 12.4° C. 

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



119° 09' 52" E.; 175 fathoms; fine S. co.; 13° C. 

 D. 5580. Sibutu Island, Darvel Bay, Borneo; 4° 52' 45" N.J 



119° 06' 45" E.; 162 fathoms; br. S. co. 

 Pacific: Australia (Hincks, MacGillivray, etc.) 

 Geologic distribution. — Miocene (Helvetian) Touraine and Gard, 

 France (Canu collection). Miocene (Tortonian), Austria-Hungary 

 (U. S. National Museum). Miocene of Australia (Waters). 

 Plesioty pes. —Cut. Nos. 7908-7911, U.S.N.M. 



