642 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



color with numerous fine reticulations of poppy red. Along the 

 median line occurred a longitudinal band of a yellowish-white color. 

 The ventral surface was almost exactly similar in color and mark- 

 ings to the dorsal, excepting the purplish-black band, which was 

 more or less broad. The internal structures were discernible with 

 more or less distinctness by tubular white markings. 



The state of preservation makes it very difficult to detect the 

 arrangement of eyespots with any degree of accuracy. The eyespots, 

 which are exceedingly numerous, are scattered over the tentacular 

 flaps and also occur forming a single circular cluster slightly pos- 

 terior to the tentacles. 



The mouth, which leads into the pharyngeal cavity with the 

 pharynx plicated, appears to open at the hind end of the first fourth 

 of the body, and the ventral sucker lies a little behind the center 

 of the body. 



The present specimen, though sexually mature, was unfortunately 

 in an unfit state for close examination of the genital organs. 



In his description of the species from Singapore Harbor, Colling- 

 wood gives the color of the body as a rich velvety olive green, but 

 in his figure the body is shown rather as black. Although there 

 exists a small difference in the ground color, as is evident from the 

 above, I feel justified in identifying the present specimen with 

 Collingwood's species. 



The present species appears to be closely allied to Pseudoceros 

 ftavomarginatus Laidlaw, 5 a species from Minikoi, Laccadive 

 Group, so that they may be identical; and it, according to Laidlaw, 

 is also known to occur in Hulule and Minikoi. 



6. PSEUDOCEROS CONCINNUS (Collingwood). 



Plate 1, fig. 6. 



Proceros condnnus Collingwood, 1876, Trans. Linn. Soc, ser. 2, Zool., vol. 

 1. p. 90.— Lang, 1884, Naples Monogr., p. 593. 



Only a single example, which, although showing a small differ- 

 ence in the feature of its tentacles, appears to be identical with 

 Collingwood's Proceros condnnus from the islands of Labuan and 

 Pulo Daak near the mainland of Borneo, was found on the head of 

 coral in about 2 feet of water on the shore of Papahag, Tawi Tawi, 

 in February. No specimen unfortunately came under my direct 

 observation; and the following is based upon Professor Bartsch's 

 note and colored drawing. 



The body was of a thin leaflike shape in the living state, its lateral 

 margin being slightly frilled. The tentacles appeared as two 

 S-shaped, folded outgrowths of the anterior body margin, differ- 



5 Laidlaw, 1902, Fau. & Geogr. Maldive & Laccadive Archtp., vol. 1, pt. 3, p. 298. 



