1889.] 



ANATOMY OF GONATUS FABRICII. 



129 



The only other recent addition to the literature of the subject is a 

 short paper by Malcolm Laurie \ 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 tliis 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 B 



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 laonius. 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 yi^-inch oil immersion of Zeiss ; they seem 

 perfectly homogeneous and do not take up the stain. Over the sur- 

 face of the cells is spread a thin layer apparently of secreted material. 

 It stains faintly, is dull and turbid and not strongly refractile ; its 

 uftper surface is often iiregnlar. It is most distinct a little distance 



from the margin. 



Quart. Journ. Micr. Sci. xxviii. 1888. 



