PHILIPPINE POLYCLAD TUKBELLARIANS. 639 



The body in life was elongate-oval in shape and had the margin 

 very strongly frilled. The frontal margin was folded in a pair of 

 tentacular horns about 5 mm. apart. Irregularly distributed all 

 over the dorsal surface were numerous slenderly conical papillae 

 of varying size. The worm in the expanded state measured 85 nun. 

 in length and 38 mm. in breadth at the middle of the body. 



Almost completely round the extreme margin of the body, on the 

 dorsal surface, was a pale pearl-gray stripe, just inside which was 

 a broad band of a sooty color, gradually shading inward to plum- 

 beous. A somewhat darker shade occurred along the median line 

 from the tentacles to near the end of the body. Most of the dorsal 

 papillae were generally of a white color, excepting at the tip, which 

 was orange. Frequently some were colored orange throughout. The 

 ventral surface presented a marginal band of pearl gray and a broad 

 purplish sooty one within this, just as on the dorsal. The rest of 

 the surface was of a pearl-gray color with a narrow median white 

 streak which extended posteriorly from a short distance behind the 

 anterior margin. 



The present species is on the whole most closely allied to Thysano- 

 zoon brocchi (Grube) of cosmopolitan distribution, which varies in 

 color to some extent. But it can be distinguished from this by the 

 possession of an unpaired penis. 



Genus PSEUDOCEROS Lang. 



3. PSEUDOCEROS HANCOCKANUS (Collin?wood). 



Plate 1, flg 3. 



Proceros hancockanus Collingwood, 1876, Trans. Linn. Soc, ser. 2, Zool., 



vol. 1, p. 91. 

 ? Stylochopsis malayensis Collingwood, 1ST6. Trans. Linn. Soc, ser. 2, 



Zool., vol. 1, p. 94. 

 Prostheceraeus hancockanus Lang, 1884, Naples Monogr., p. 567. 

 Pseudoceros malayensis Bock, 1913, Zool. Bid. f. Uppsala, vol. 2, p. 258. 



Professor Bartsch secured but one specimen. While fishing with 

 a submarine light in February, near Tominado Island, Tawi Tawi, 

 it was found swimming on the surface of the water. It may be iden- 

 tical with Proceros hancockanus. 



The body in the living state was of a thick, broad, leaflike shape 

 with frilly margin. The tentacles appeared as two S-shaped lobes 

 of the anterior margin of the body. When the worm was at rest, 

 they were folded back on the dorsal surface. In the expanded state 

 the body measured 46 mm. loiig by 24 mm. across the widest part 

 at the middle. 



The dorsal surface was of a blackish-brown color with a much 

 darker shade along the median line, and was margined nearly all 



