270 Pub. Puget Sound Biol. Sta. Vol. 2, No. 49 



Filippi (1865-1868), each of whom has described a species. Sir Charles 

 Eliot (1902) has contributed to our knowledge of the morphology of the 

 genus through comparative studies of Melibe and Tethys and has given an 

 account of the feeding habits of Melibe. No detailed study of Melibe 

 leonina has been made. Our knowledge of the species rests largely on the 

 brief description and figure published by Gould (1852). 



The known distribution of Melibe is restricted to the Pacific and 

 Indian Oceans. On the eastern side of the Pacific 2 species have been 

 described: e. g., M. leonina (Gould) in 1852, from Port Townsend, Wash- 

 ington, and M. pellucida (Bergh) in 1904, from the coast of Washington 

 near the mouth of the Columbia River. On the western side of the Pacific 

 various species have been found by Bergh (1875, 1880, 1884, 1888, 1892, 

 1880-1892, 1902, 1904, 1907-1908) from the Japanese islands to Singapore. 

 One species (Melibe pilosa) has been described by Pease (1860) from the 

 Sandwich Islands; another {Melibe australis) by Angas (1864) from Aus- 

 tralia; and still another (Melibe papillosa) by De Filippi (1865-1868) 

 from Japan. Melibe rosea was described by Rang (1829), and Melibe 

 fimbriata by Alder and Hancock (1864) and Eliot (1902) from the Indian 

 Ocean. To the present time no species of this genus seems to have been 

 found on the coasts of the Atlantic Ocean. There and in the Mediterranean 

 Sea Tethys has its home. 



The specimens of Melibe upon which Gould (1852) founded the species 

 M. leonina were collected at Port Townsend, in the northern part of Puget 

 Sound. When the Puget Sound Biological Station was established in 1904 

 in the San Juan Archipelago, only about 50 kilometers from Port Townsend, 

 it was found that this animal was not uncommon in the vicinity of the 

 Station, although, like many pelagic organisms, its abundance was subject 

 to great fluctuations. In the summer of 1912 it was particularly abundant, 

 great numbers appearing among the fronds of Nereocystis which drifted 

 past the floating dock in front of the Station. At this time Professor H. L. 

 Osterud of the University of Washington gathered and preserved a con- 

 siderable number of specimens. The largest obtained at this time were 

 6 cm. long. The time of collection was the latter part of July. In the 

 season of 1913 very few were seen. In 1914 the writer found several speci- 

 mens of large size, 8 to 13 cm. long. These were taken from the floating 

 leaves of the eel-grass (Zostera marina^. In the summer of 1915 only 2 

 specimens were found. It appears that the genus Tethys has a similar spas- 

 modic recurrence as has been noted by observers in the Mediterranean. The 

 appearance of Melibe does not appear to be determined by any particular 

 season, since Professor Osterud found specimens spawning when visiting 

 the Biological Station early in March during the spring of 1916. 



