HYDROZOA — RITCHIE. 819 



Stations 44, 47, 48, and 54. , , , . 



Specimens of this widely distributed, epizoic species Qccm* on 

 several hosts from several stations. The, .abuyd{j,nce of, the 

 hydrothecte which bristle upon the weathered axis of an Isi]d 

 Alcyonarian from Station 47 is specially remarkable, the growth 

 resembling that of Lafoea contorta, Nutting, frpni Hawaii, which 

 differs from the present species only in the fact that annular 

 thickenings of the hydrothecal wall are absent from the adnata 

 portion, yet in Nutting's figures** striations are shown on some 

 of the hydrothecfe. • There is much variation in the relative pro- 

 portions of adnate and free portions, this being in the main due 

 to extensions to which the free portion is liable by the addition 

 of new margins. As many as six. repetitions may occur, more 

 than doubling the length of the free portion. In tlie following 

 table of dimensions, therefore, I give, as bejng more constant, the 

 lenoth of the primary h^'drotheca of the repeated sei;ies. There 

 is also much variation in the distinctness of the striations which 

 occur on the horizontal portiqw ; for wjiile these are well marked 

 in some specimens, in others, they are almost invisible, and the 

 latter are hard to. distinguish from hydrothecse of Filellum ser- 

 pens, on which also. f^int striations sometimes occur. 



Gonosome. — The gonosome, of which I have seen no description, 

 is aggregated in coppinia form, an elongated cluster surrounding 

 the surface upon which the colonies are creeping The essential 

 part of the structure is very similar to that of Filellum serpens, 

 the gonangia appearing in surface view as close-set irregular 

 polygons, each with a slightly raised circular aperture. Between 

 these in one case project long tubes, which stand out stiffly from 

 the surface of the coppinia, unlike the curling, close-lying indi- 

 viduals of F. serpens. In the only other example I have seen, 

 the tubes do not project, but instead lie closely apposed to each 

 other, parallel to the surf-ace of the coppinia. . In cross section, 

 these tubes are almost rectangular, for they are- compressed in a 

 direction at right angles to the surface of the coppinia. Thus 

 the coppinia is enclosed in an irregular double-walled case formed 

 of close-set, adnate tubes, and having a distant resenjblan.ce to a 

 structure oi basket-work. 



In cross section of the coppinia tliere was seen, surrounding 

 the Alcyonarian axis upon which the colony was creeping, an 

 irregular layer of tubes of small calibre, oval in cross section, 

 their long axis parallel to the surface of the substratum. These 

 correspond to the netwoik of tubes which forms the rhizoidal 

 structure of the colony in general. From them arise radially 

 long strong walhd gonangial tubes which sometimes at least (as 



^Nutting— Bull. U.S. Fish Comm. for 1903, pt. iii., 1905, pi. ix., figs. 

 8, 9, p. 945. 



