| Abstract: | Observations are recorded for Ascophyllum, Pelvetia, Himanthalia,and Dictyota in addition to Fucus which has already been describedin a previous paper. Fibrillar disintegration of cilia has beenobtained in all except Pelvetia, in each case to give nine peripheralstrands and a central pair. This corrects a previous error forthe hind flagellum of Fucus. Some facts are given regardingthe internal organs associated with the parts of the cilia insidethe body in Himanthalia and Dictyota. A proboscis similar tothat previously described for Fucus has been demohstrated inAscophyllum and Pelvetia, but is absent from Himanthalia andDictyota. Himanthalia differs from the other Fucoids in therelative lengths of front and hind flagella. Dictyota has onlya single flagellum. In all, the front flagellum is a Flimmergeisselwith two rows of hairs, which, in certain cases, notably Himanthalia;have very long hair points. In Himanthalia there is a largespine near the distal end of the front flagellum borne on onefibril of the peripheral series. In Dictyota there is a rowof smaller spines at the front end of the flagellum borne ina line between the two lateral rows of hairs. These spines inDictyot can be used as evidence regarding the internal symmetryof the whole cilium which is summarized in a diagram. |
