AND THE MALES OF CERTAIN CEPHALOPODS. 123 



guishes externally two sets of suckers, branchiae in the form of 

 villosities, and an oval abdomen from whose aperture the penis 

 makes its exit. The skin is composed of two layers; of an epi- 

 dermis with polygonal cells, and of a corium composed of inter- 

 woven undulated fibrils, in the midst of which contractile pig- 

 ment-cells are deposited chromatophora such as are met with 

 in all Cephalopods, without exception. The muscular system is 

 composed of bundles belonging to the suckers, and besides of a 

 very strong muscular tube, which serves as a support to the 

 whole body, and in the interior of which is found a cylindrical 

 cavity almost entirely filled by a longitudinal tube which M. Kol- 

 liker calls the intestine. The muscular tube itself is composed 

 of three layers of fibres, the median being longitudinal, whilst 

 the other two are circular. M. Kolliker is unable to give any 

 complete account of the nervous system ; but having seen under 

 the microscope a true ganglion containing six ganglionic cor- 

 puscles, he is certain that nerves exist, and he believes that a 

 fine white thread, which he once met with upon the upper sur- 

 face of the intestine, is truly a nervous cord. M. von Siebold, 

 on the other hand, remarks, that he has found in the axis of the 

 body of the Hectocotylus of the Tremoctopus a nervous cord 

 whose greatly developed ganglia correspond in number with the 

 lateral suckers. M. von Siebold does not believe that the Hec- 

 tocotyli have any digestive system. M. Kolliker speaks doubt- 

 ingly : he describes a longitudinal tube situated in the centre of 

 the muscular tube, w r hich it almost wholly fills. This tube is 

 composed of two membranous layers ; according to his account 

 it is closed posteriorly, and terminates perhaps by a fine aper- 

 ture visible only in the recent animal and situated at its ante- 

 rior extremity. The tube contains nothing but conical masses, 

 arranged regularly, and exactly corresponding in number to the 

 suckers. M. Kolliker adverts also, as a supplement to this de- 

 scription of the intestinal system, to the existence of small ellip- 

 tical apertures arranged in line to the number .of four or five, 

 upon the ventral surface, below these conical bodies contained 

 in the intestine. These little apertures are prolonged into as 

 many fine canals which are directed upwards towards the central 

 muscular tube ; but he could not decide exactly if they entered 



