WEST COAST HYDEOIDS 7 



appear and others as gradually' come in. At the present time, out 

 of a total of 196 species, there is record of 155 species from the 

 Vancouver Island Region and north of it, and 88 south of that 

 region. No less than -47 or 24% of the whole number are common 

 to the two, these being divided up as follows: Gymnoblastic 

 forms 9, Campanularians (here used in the broad sense of all 

 hydro thecate forms except Sertularians and Plumularians) 20, 

 Sertularians 11 and Plumularians 7. Furthermore, 22 species 

 that are found north of Vancouver Island, are found in the Van- 

 couver Island Region as well as in the Region south of it. 



Referring again to Dr. Clark's paper% he says "There is little 

 doubt that when the fauna has been more thoroughly investigat- 

 ed, the number of Hydroids may be at least doubled. Such a 

 variety as exists on the New England Coast can hardly be ex- 

 pected from our Pacific shores south of Vancouver Island, for the 

 waters there do not afford the same diversity of temperature." 

 The basis for this latter conclusion was rather insufficient also. 

 Since that time, the work that has been done south of Cape Flat- 

 tery, has been limited almost entirely to the work of Dr. Torrey, 

 which, however excellent it has been, has been largely confined 

 to the vicinity of San Francisco and San Diego with some inter- 

 mediate points, and a little dredging by the ' ' Albatross ' ', report- 

 ed as yet only so far as the Sertularians and Plumularians are 

 concerned, yet the number of species has increased from 24 to 88, 

 and as far as I can see, if the waters off shore from Cape Flattery 

 to San Francisco are carefully worked, there is no reason to sup- 

 pose that the latter number might not be doubled, or that it 

 might not favorably compare with an equal amount of Coast-line 

 on the Atlantic side of the continent. 



However that may be with regard to the coast south of Cape 

 Flattery, there is no stretch of the Atlantic Coast equal in extent 

 to that of the Pacific Coast to the north of Cape Flattery that can 

 offer such variety of favorable conditions for Hydroid growth as 

 there is to be found in that region. The broken nature of the out- 

 line, the presence of innumerable islands, large and small, 

 throughout the entire length, in many cases separated by great 

 depths of water, making a variety of currents and tide-waves, 

 and a wide range of temperature, though the cold, which the 

 Hj^droid usually prefers, is predominant. The profusion of plant 

 life everywhere evident, is a good indication of the variety in 



1 Hydroids of the Pacific Coast, 1876, p. 251. 



