三崎産後鰓類の2新種に就て On Two New Opisthobranciata from Japan
In accordance with the suggestion of the late Dr.Charles ELIOT, then the British Ambassador to Japan, and the advance of the late Dr.SEITARO GOTO I began to undertake a thorough study of the whole species of Opisthobranchiata found in this country, and especially at Misaki. I have made a careful study of Aglaja and Berthella found off Misaki, and have arrived at a conclusion that the following two species are now to science:- I. Aglaja iwasai sp. nov.^* There is only one species (Aglaja gigliolu TAPPARONE-CANEFRI, 1874) of Aglaja known to be Japanese, But think Aglaja iwasai is to be sharply differentiated from it, the reason being as follows: (1) The shell is entirely different. (2) The size of body is much lager. (3) The color is different. (4) It has no flagellum of filament at the tip of the left separated lobe of the mantle. Aglaja iwasai is also different from all of the known species of Aglaja. II. Berthella gotoi sp. nov.^<**> This species in its general appearance reminds us to a certain extent of Berthella borneensis of BERGH, 1905, but differs from it in te following points: (1) The color of the living specimen is a grenadine red with many small white papillae. (2) The size of the animal is smaller. (3) the gill lamellae are less in number (15). Exactly speaking, Berthella borneensis has 30 lamellae on both sides. (4) the shell is rather small and differs in its form. The ratio between the shell length and width is 1.4, while Berthella borneensis has 2.0. (5) the number of the teeth of the radula is not the same. This form can also be destinguished from all recorded species.