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Show 198 MR. P. S. ABRAHAM ON THE [Mar. 6, merated 17 (a few of them new) from the Mediterranean ; Philippi, who recorded 23 from Sicily; Loven, who found 18 (5 new) on the Scandinavian shores; Verany, who described 11 new species, and enumerated 11 others from the Gulf of Genoa, and who afterwards catalogued 23 from the environs of Nice. Kelaart has described 42 from Ceylon ; Angas, 21 from New South Wales ; Alder and Hancock, 32* from India and Ceylon ; Gould, 9 species from Eastern North America, and 14 from the Pacific Isles; Pease, 28 from the same part of the world. Recently Bergh has figured, described, or named about 32 species of Anthobranchiate Nudibranchiata from the Philippine archipelago. In addition, De Blainville, Leach, Gray, Fischer, Morch, and several other naturalists have more or less studied the group, and have from time to time added species to the list. With the exception of Cuvier, Delle Chiaje, Johnston, Alder, Hancock, Embleton, and Bergh, few observers have examined the anatomy of this section of the order. Between the years 1845 and 1855, appeared Alder and Hancock's ** Monograph of the British Nudibranchiate Mollusca.' This is by far the most important work that has ever been writlen on the naked-gilled Mollusca. In it 39 species of our native Authors ranohiata areincluded, and 29 of them minutely described and beautifully figured. Twenty-two were new or but recently described by the authors ; and, for the first time, something like a philosophical classification of the Nudibranchiata was proposed. Upon that arrangement is based, in a great measure, the plan adopted in the present paper. The Anthobranchiate naked-gilled Mollusks are found all over the globe, frequenting, for the most part, rocky shores between high- and low-water mark. Some, however, have been dredged from comparatively deep water, or have been found on floating seaweed. They appear to be more numerous, larger, and with more brilliant colours in the warmer seas, especially in those of the eastern hemisphere. Some of them have a wonderfully wide "habitat." In the British Museum there are specimens of the common European Boris tuberculata, which were obtained from New Zealand and from Vancouver Island. Lamellidoris bilamellata, also one of the commonest of North-European Dorididae, is found on both coasts of North America ; and several other instances might be given. The American forms are, as a rule, few*, small, and obscure in colouring. The small, brightly coloured Chromodorides are all inhabitants of warm seas; while the Polycerides have principally been discovered on the colder shores. The Indian and Pacific Oceans seem to be the head quarters of the remarkable tongueless Doridopsidse ; but a few have extended so far north as the Mediterranean. |