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Show 664 MR. .T. GRAHAM KERR ON THE [June 18, 7. On some Points in the Anatomy of Nautilus pompilius. By J. GRAHAM KERR, Christ's College, Cambridge. [Received June 17, 1895.] (Plates XXXVIII. & XXXIX.) I. Introduction, p. 664. II. The Body-cavity of Nautilus, p. 664. III. The Male Genital Ducts and Penis, p. 671. IV. The Buccal Nervous System, p. 673. V. The Innervation of the " Inner Inferior Lobe," p. 675. VI. The Post-anal Papilla? and Nerves, p. 676. VII. The Spermatophore-receiving Apparatus, p. 677. VIII. The Morphology of the " Arms" of Cephalopods, p. 678. IX. The Phylogenetic Relationships of the Cephalopoda, p. 683. X. Summary of Conclusions, p. 685. Explanation of the Plates, p. 689. I. Introduction. During the year 1893 Mr. A d a m Sedgwick very generously placed at m y disposal a number of specimens of Nautilus pompilius with the suggestion that I should make an examination of their structure. The specimens were twenty-five in number, of which, however, the great majority were very young and immature. Owing to the method of preservation and to several months' sojourn in sawdust moistened with spirit, the condition of the specimens was usually such as to render them unfit for histological study. Fortunately one of them was sufficiently good to allow the use of the section-method to confirm the results of minute dissection. In the following somewhat fragmentary paper it is m y purpose to touch upon what seem to m e the more important points at which 1 have arrived, hoping at some future date, if able to obtain properly preserved specimens, to extend m y investigations and to fill up the obvious lacunae. I can hardly adequately express the obligation under which I am to M r . Sedgwick for the generous gift by which he has made these investigations possible and opened the way to what, however poor its results are so far, has proved a study of absorbing interest, and also for much kind advice and encouragement. To M r . Wilson also a word of thanks is due for the care with which he has attended to the illustrations. II. The Body-cavity of Nautilus. It is now generally recognized that the body-cavity in the higher Metazoa may be referred to either of two very distinct types. The first of these, typically developed in Annelida and Vertebrata, is lined by a definite characteristic epithelium, from some of whose cells arise the genital products, while others become the renal excretory cells. It appears at au early stage in development as a more or less continuous space, and it communicates with the |
