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Show 1889.] ANATOMY OF GONATUS FABRICII. 129 The only other recent addition to the literature of the subject is short paper by Malcolm Laurie l, which adds little of importance to our knowledge. A large number of the transverse sections which I made through the anterior region of one of the small specimens of Gonatus showed the funnel-organ. Its state of histologieal preservation was far from satisfactory ; indeed its extreme sensitiveness to the ordinary reagents has been remarked by all those who have examined it in the fresh condition. Since, however, it is unlikely that any one will have the opportunity in the near future of examining this species in a state of nature, it seems better to place on record the facts observed, so that they may serve at all events for comparison. This organ is mainly due to a great thickening of the epithelium of three areas in the funnel. One of these is median and lies upon the large venous sinus which passes down the ventral aspect of the animal, separated from it merely by a thin membrane, whilst the other two occupy portions of the two lateral walls of the funnel and are so situated that when the funnel contracts they become applied to the median portion of the organ (compare woodcut). A. Transverse section through the funnel of an advanced embryo of Sepia, to show the form and disposition of the funnel-organ.-B. A similar section of a young specimen of Taonius. m.p., median pad ; l.p., l-p., lateral pads; si., ventral wall of the funnel; v.c, vena cava. The cell-boundaries in my sections are very difficult to make out (Plate XIII. fig. 8); they are most distinct in the lateral portions of the median pad, and here it is clear that the pad is only one cell thick, its component elements having become extremely elongated. The nuclei are situated at various points in the cell, generally somewhere in its middle third ; they are small and do not stain so deeply as usual. The distal extremities of the cells are occupied by curious highly refracting subglobular bodies. No structure whatever could be made out in these globules, even under a ^-inch oil immersion of Zeiss; they seem perfectly homogeneous and do not take up the stain. Over the surface of the cells is spread a thin layer apparently of secreted material. It stains faintly, is dull and turbid and not strongly retractile; its upper surface is often irregular. It is most distinct a little distance from the margin. 1 Quart. Journ. Micr. Sci. xxviii. 1888. |
