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Show 1881.] MOLLUSCA OF ' LIGHTNING' ETC. EXPEDITIONS. 693 and from the mouth by the small valvular opening referred to, and having its sides supported behind by the expanded hyoid bones, constitutes a most perfect exhauster; while the broad epiglottis, permanently folded over the larynx in front so that its aperture is directed upwards towards the spine, and the great size of the fibrocartilaginous masses extending forwards from the arytenoid cartilages to the epiglottis (fig. 5, c, p. 690), effectually guard the glottis, preventing any part of the food, such as the small fig-seeds, from being drawn into the air-passages. In the males of E. monstrosus, franqueti, comptus, and pusillus, permaneut inflation of the pharyngeal sacs is rendered possible by the manner in which, as above described, the nasal and oral cavities are capable of being completely shut off from the pharynx. Considering the large size and position of the apertures by which these sacs communicate with the pharynx, it would appear at first sight that most of the food entering the pharynx must find its way into them. This difficulty is removed if we allow that suction by means of the inspiratory action of the lungs has any thing to do with drawing the semifluid food into the pharynx; for it is evident that the same action would cause the walls of the sacs to collapse inwards upon the apertures, and so close their communication with the pharynx at the very time when it was most needed. 5. O n the Mollusca procured duriug the ' Lightning' and ' Porcupine' Expeditions, 1868-70. (Part III.1) By J. G W Y N JEFFREYS, LL.D., F.R.S., F.Z.S. [Eeceived May 20, 1881.] (Plate LXI.) CONCHIFERA {continued). Family VIII. KELLIID^E. 1. P Y T H I N A SETOSA, Dunker. Coralliophaga setosa (Dunker), Grube, Die Insel Lussin und ihre Meeresfauna, 1864, p. 48. Scintilla recondita, Fischer, Les Fonds de la Mer, 1872, p. 49, pi. ii. f. 3. 'Porcupine' Exp. 1870 : Atl. St. Tangier Bay ; Med. 50, 50a. Distribution. Arcachon to Mogador, Sicily, and Adriatic. Depths 5 to 86 fathoms. Fossil. Pliocene : Monte Mario and Ficarazzi. Sportella caillati, Conti, and Kellia macandrewi, Fischer. It belongs to Pythina in respect of the hinge as well as of the peculiar divaricating sculpture. 1 For Part I. see P. Z. S. 1878, p. 393; for Part II. see P. Z. S. 1879, p. 553. |