igil] ASCIDIANS FROM THE COASTS OF CANADA. 117 



Parasitic Protozoa occur in the glandular folds of the stomach in 

 most species and in the 'liver' of Caesirids [Molgulids] and Tethyids 

 [Cynthiids]. An Isopod was found in the endostylar vessel of Styela 

 gibbsii and Pyura haustor. 



Although Ascidians are not used for food on this continent, there 

 are a number of species that might be so used. In most of the forms the 

 musculature is so small in amount that when the test has been removed 

 the great bulk of the animal consists of sea-water. In theStyelids and 

 Tethyids, however, the musculature is well developed and frequently 

 quite thick. Tv/o species of Tethyum, very similar to or the same as 

 those of our coasts, are, according to Oka, eaten by the Japanese. The 

 inhabitants of Peru and Chili use as food two species of Pyura that occur 

 on their coasts and species of the genus Microcosmus are exposed for sale 

 in the markets of southern Europe (Grube). 



The Holosomatous Species of the West Coast. 



The complete account of these species was sent in July, 19 10, for 

 publication in the Report of the Biological Stations of Canada. In 

 the following account it is intended to give provisional diagnoses of the 

 new genera and species, as well as some notes on the other species. The 

 full extent of the variation noted in the various species is not always 

 given in this account. Further study has shown that certain changes 

 should be made in the original account and these have been incorporated 

 in this article. 



The writer is indebted to the Rev. Mr. Taylor for a large amount of 

 material from Departure Bay, Hope Island, Banks Island, Goose Is- 

 land, Lowe Inlet, China Hat, Stephen Island, Port Simpson, Prince 

 Rupert, Rose Spit and Hecate Straits. Prof. Macoun communicated 

 to the writer the collection of the Geological Survey, which contained a few 

 specimens collected by Dr. Dawson in 1885, and a large amount of ma- 

 terial from Departure Bay and Ucluelet, collected by Prof. Macoun and 

 his assistants in 1908 and 1909. 



Many of the Ascidian genera are inconveniently large and hetero- 

 geneous, e.g. Tethyum [Cynthia, Halocynihia sett Pyura], Styela, Caesira 

 [Molgula], and Phallusia [Ascidia]. It would be a distinct advance to 

 have these genera divided into smaller natural groups, so that the re- 

 lationships of the species would be shown. I have attempted a division 

 of Tethyum, Styela and Phallusia as far as the material at my disposal 

 would permit. Some of these groups are quite small and it is question- 

 able whether they should have the rank of genera. If they are given 

 generic rank temporarily, it will call attention more forcibly to the char- 

 acters which seem to be of importance in separating these groups. Many 



