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Show 1903.] FROM EAST AFRICA AXD ZANZIBAR. 355 Trippa Bergh. 1 ° 1 - J. 1 _ - 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. „ u, 'BUOUM yn. u. ±L.,. „ monsoni, sp. n. Fracassa ii Bergh. tuberculosa. Halgerda Bergh. n ii willeyi, sp. n. (From the Loyalty Islands.) wasinensis, sp. n. Kenirodoris Bergh. n rubescens Bargh. Platydoris Bergh. n ii n ii n ii ii Sclerodor ii n ii n n eurychlamys Bergh. scabra (Cuvier). formosa ? (A. & H.). elUotil (A. & II.). pulchra, sp. n. incerta, sp. n. papillata, sp. n. is Eliot, gen. n. osseosa (Kelaart). tuberculata, sp. n. minor, sp. n. rubra, sp. n. coriacea, sp. n. Asteronotus Ehrenberg. 30. ,, hemprichi Ehrenberg. The Cryptobranchiate Doricls are distinguished by having branchiae which are completely retractile into a permanent pocket. The rhinophores also are retractile into permanent pockets and are perfoliate. A radula is always present. In number of species they form one of the richest groups of the Nudibranchiata, but they show less variety of form than the Dorididae Phanero-branchiatae, and it is not easy to find good generic characteristics. The most distinctly marked group is that consisting of the large genus Chromodoris (with more than 100 species) and some allied genera such as Casella and Ceratosoma. These possess a characteristic shape, lip-plates, a radula with differentiated teeth, and simply pinnate branchiae. Well characterised genera are also found in the Miamiradae {Miamira, Orodoris, Sphcerodoris) and the Cadlinidae {Cadlina, Tyrinna). There remain the five subfamilies mentioned above, which agree in being usually flat and oblong in form and in having a radula without a central tooth, consisting of numerous laterals which are generally hamate and uniform, though often smaller near the rhachis and degraded or denticulate at the outer end of each row. Anyone who describes new forms of these Dorids, however much he may disclaim any such ambitious task as a revision of 23* |