I HAVE recently been able to examine alcoholic specimens of Jlesania lanceolata (otherwise known as Vanganella Taylori), Gray, and Zenatia Deshayesii, Iieove, from New Zealand. These were collected whore they had been thrown up by the waves, and were so permeated with fine siliceous sand that thin sections could not be cut for fear of ruining the microtome. They were, however, otherwise perfect, and, since the anatomy of these forms has not been described, it seems desirable to give some

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... of the more conspicuous features of their structure. RESANIA LAJTCEOLATA, Gray. In this very inequilateral form the posterior part of the valves is disproportionately short, and the pallial sinus is short, extending forward only to the thickened ray which passes downward from the umbonal region of the valve. The siphons are naked, slender, closely united to their very tips, the orifices nearly in the same plane and surrounded by small papillae, much retracted in the specimens. The mantle has a thickened edge, smooth for the most part, but, near the ends of the shell, more or less papillose, with rather distant papilla). The mantle is completely open, except in the central portion of the dorsal margin, not being united even where its margins pass around the adductors. The foot is compressed, sharp-edged, pointed, large and muscular, with no obvious byssal groove, and of a lanceolate outline. Its edges are entire. The palpi are large, narrow, long, smooth externally, plicate internally, adherent near the small circular mouth. They extend beyond the posterior edge of the visceral mass, becoming distally free and twisted at the ends. The body is connected with the siphonal septum by a Q-shaped fleshy septum, from which, on each side, a smooth, fleshy, narrow flap, as long as the septum itself, hangs down into the branchial chamber. Outside these flaps, and eeated on the lateral borders of the fleshy septum, are the gills. These present some peculiar features, the most obvious of which is that the gills of the two sides are not symmetrical; and, further, that on one side, and in some cases on both sides, the plicate lamina) are discontinuous. The ctenidium of tho left side is short and small, the outer lamina smaller than the inner, both dwindle to a point and cease before reaching the vertical of the visceral mass, and there is a distinct vacant space with no trace of a pendant lamina between the anterior termination of this part of the ctenidium and the sinus between the posterior parts of the palpi. Further forward, between the upper and lower palpi, a new lamina, corresponding to the inner direct and reflected lamina of the ctenidium, is developed and attains a respectable Eize, being wider than the palps and extended forward, diminishing in 8G ritOCEEDIXCS OF THE SIALACOLOGICAT. SOCIETY.