1899.] NATURAL SCIENCES OF PHILADELPHIA. 517 



Pleurobranchus delicatus Pse. 



Three specimens from Safotu, Savaii, in July. The animal 

 agrees with Pease's description (Amer. Jour, of ConcJwlogy, 1868, 

 p. 79), but is not very like his plate, being smaller and of a much 

 brighter orange except on the back, where the black viscera can 

 be seen through the skin. Branchia and orifices very prominent. 



Platydoris Bergh. 



Two species of this genus l^scabra and arrogans) are common 

 under stones on Apia reef. They both grow to a length of 

 about three inches, and are characterized by their flattened form, 

 wide mantle, with irregularly indented edges, and a peculiar hard 

 and leathery texture, which distinguishes them at once from all 

 other Dorids which I have seen. They are sluggish in their move- 

 ments and do not appear to be protected by their coloration. P. 

 scabra {= Doris scabra Q. and G. ) grows to be about three inches 

 long. The outline is an irregular oval, the edge of the ample 

 mantle being wavy. The color is white, with irregular blotches 

 of brown produced by aggregations of small spots. The branchial 

 rosette is yellowish, sixfold and very voluminous and delicate. 

 Edge of foot brown, but sole and under surface of mantle white. 

 Labial tentacles small, white and tapering. The branchial aper- 

 ture is clearly defined and starlike. Plabjdoris arrogans Bgh. 

 {=1 Doris crtienta Q. and G. ) has the same external characters 

 as PI. scabra, but the markings are formed, not by minute spots, 

 but by fine lines. In addition to them there are on the back 

 four or five splashes of vivid red, looking like red ink, which disap- 

 pear in alcohol. 

 Discodoris fragilis (A. and H.), Bergh. 



Doris fragilis Alder and Hancock, Traas. Zool. Soc, Vol. 5, 1864, 

 pp. 117, 38. From east coast of India. 



This animal is common on Apia reef. In life it is brownish 

 green, mottled with darker shades of the same color, the foot and 

 under surface of the mantle being similarly marked. The rhino- 

 phores and branchial rosette are brownish and the labial tentacles 

 white and pointed. The v/hole body is flat and oval, and the 

 length from two to three and a half inches. 



The creature is remarkable for its extraordinary powers of self- 

 mutilation. When handled, it throws off part or the whole of 



