WEST COAST HYDROIDS 73 



operculata together, giving the latter name to the three species. 

 Hartlaiib^^ goes a step farther, by including as well, Dynamena 

 bispinosa Gray, with these three species, all under the name S. 

 operculata. Evidently none of these investigators have seen a 

 ispecimen of »§. furcata, and unfortunately Clark's drawings do 

 not bring out many of the characteristic features. His descrip- 

 tion too, is rather meagre, though in it certain features distin- 

 guishing this from these other forms are mentioned. Torrey, 

 particularly in his 190-1 paper, makes note of some of these dif- 

 ferences, but as he had not seen d'Orbigny's drawings, only one 

 of which was copied by Nutting, he was not in a position to ap- 

 preciate all the differences that exist. 



The mode of growth in the two cases is markedly different. D. 

 pulcliella, according to d 'Orbigny,""^ may be a quarter of a meter 

 long, is much and irregularly branched, and is attached in the 

 usual way to the surface of a shell. None of the specimens of 

 S. furcata are more than three-quarters of an inch in length, un- 

 branehed ; each stem is attached to a stolon ' ' by a short, slender, 

 twisted process, about the length of an internode". The stolon 

 which may be quite long, is not very sinuous, and in all speci- 

 mens to hand, is growing attached to the surface of eel-grass. 

 The pairs of hydrothecfe with the exception of the first two or 

 three towards the base, are in contact on the one side of the stem, 

 which Trask calls the back and Torrey the face. There is no in- 

 dication in any of d'Orbigny's figures, that t\\ej come together, 

 but rather they are shown to be noticeably apart. I see no sign 

 of the double annulation at the nodes that d'Orbigny mentions, 

 and the annulations are not so regular as he figures them. The 

 gonangia appear to be similar in the two species. In S. furcata 

 they are restricted to an area near the base of the stem, whereas 

 in D. pulcliella, on account of the extensive branching, they have 

 a wide range. In both eases they have their origin just below the 

 bases of the hydrothecfe. 



Trask 's description agrees very well with Clark's except that 

 he speaks of the stolon as the main stem or rachis, which is ' ' ad- 

 nate to the various marine alga? on which it grows, and often 

 quite embedded in the fronds of marine plants". His descrip- 



55 Die Hydroiden der Magalhaenischen Region, 1905, p. 664. 



56 Voyage dans L 'Amerique Meridionale, 1839, p. 26. 



