Page:Journal of botany, British and foreign, Volume 34 (1896).djvu/418

 888 NEW OR CRITICAL BRITISH MARINE ALG^, terminal tetraspores, and by the more regularly tapering thallus- filaments. Mr. Brebner has sent me from Plymouth specimens of a plant which agrees very exactly with Hauck's description of Cnioriella armorica, but as this name cannot, for the reasons given above, be retained for the plant, I have been compelled to give it a new name. 12. Cruoriopsis cruciata Dufour, Elenco delle Alghe della Liguria — Commentario Crittogamologica Italiana, ii. 59 ; Zanardini, Iconogr. Phyc. Adr. iii. 25, pi. 86, figs. 1-4. On old shells dredged from deep water near the mouth of the Yealm, and also from the " Queen's Ground," Plymouth, G. Brebner S E.A. B. British specimens of this species agree well with Zanardini's figure and description of this species, with the single exception that the tetraspores are irregularly divided. Dufour, however, says the genus differs from Contarinia (in which the tetraspores are irregular) only in the position of the tetraspores, which do not form superficial groups ; and Zanardini says, " sufficiently clearly cruciate " (Abbastanza chiaramente quadripartite in forma di croce), and, to justify re- taining the species in the genus Cruoria, instances Hildebrandtia (where the so-called cruciate tetraspores are really irregular) as a genus in which both cruciate and zonate tetraspores occur. I think, then, I may assume that in C. cruciata the tetraspores are always irregular. According to the late Prof. Schmitz, the real difference between Cruoriopsis and Cruoria lies in the mature cystocarp. In Cruoriopsis the filaments of the gonimoblast are not united, conse- quently free chains of carpospores are formed, as in Peyssonnelia ; while in Cruoria the filaments of the gonimoblast are united by a gelatinous substance, and consequently the mature cystocarp forms a more or less irregular, compact mass of carpospores. Cruoriopsis cruciata can always be distinguished from C. Hauckii, described above, by the much smaller lateral tetraspores. 13. Cruoria rosea Crn. Fl. Finist 147. Contarinia rosea Crn. Ann. Sc, Nat. ser. 4, ix. 72, pi. iii. fig. v. a, b, c. Var. purpurea, nov. var. (Contarinia cruoriccforynis Crn. Ann. Sc. Nat. ser. 4 (Bot.), ix. 71, t. iii. fig. iv. a-d? ; Cruoria purpurea Crn. Fl. Finist. 147, pi. 18, gen. 123?). Crusts about 200-800 [x thick; tetraspores small, lateral, borne near the apices of the erect filaments, otherwise as in the typical form. On old shells dredged from the mouth of the Yealm, G. Brebner. The crusts formed by this variety are much thicker than in the typical form, and the tetraspores are produced near the apices of the erect filaments, not at their base, ; but the remains of tetraspores formed at an earlier date are sometimes to be traced at the base of the erect filaments even of the variety. The cells of the basal layer of C. rosea are several times longer than broad, and it is obvious that in a transverse section they would appear very much shorter than in a section cut in the direction followed by the cell-rows of the basal layer. These apparent differences in the size of the cells of the basal layer, the position of the tetraspores, and the thickness of the crusts, seem to be the principal characters which separate (7. rosea Crn. from C. purpurea