C02 RECORD OF CURRENT RESEARCHES RELATING TO 



bracbialo lias the same elongated form, as was signalized by Albany 

 Hancock in Ommastrcplies todarus ; the same holds good for the 

 suiira-pharyngcal lobe of all the Octopoda. In various parts of the 

 peripheral system stages of differentiation can, on comparison, be 

 made out ; the ganglion stellatum, for example, did not apparently 

 belong primarily to the mantle, but lay in the visceral sac whence 

 it sent olf nerves to the mantle ; this arrangement is still to be seen 

 in Loligopsis guttata. From this position two series of changes may 

 occur : the nerve and its ganglion may pass to the mantle, or the 

 pallial nerve may separate from the ganglion. This, seen at its 

 earliest in most of the CEgopsida, is carried further in O. todarus and 

 SepiotctUhis, till in Loligo it is carried to an extreme. Other changes 

 may occur in various other forms, and in the short, compressed body 

 of the Octopoda i^art of the pallial nerve is very considerably reduced. 

 The commissure between the brachial nerves was found to be simple 

 in all the Decapoda that were examined ; in Cirrhoteuthis a nervo 

 descends from the brachial nerve to the commissure, while in the 

 rest of the Octopoda the primitive commissure forms a closed ring,, 

 connected only by branches with the nerves. After treating of the 

 visceral nerves, different stages in which are described, the author 

 passes to the 



Excretory System. — In all known Decapod Dibranchiata there arc 

 two symmetrically disposed orifices, which appear to be primarily 

 placed in the angle of the branchifc, and thence to jiass more or less 

 upwards, and inwards ; in the Nautilus, in all CEgopsida, and in 

 SejjiotcutJiis the orifices of the urinary sacs are simple and slit-shaped ; 

 in the higher Myopsida and in the Octopoda more or less elongated 

 papilhc are there developed ; and these papillae, again, exhibit different 

 stages. 



Passing over the water-system and the digestive organs, we come 

 to the ink-bag, which is ontogcuctically a part of the hind-gut. 

 From the simple embryonic condition two series of differentiations 

 can be made out ; one jiasses through the Decapoda to Sepia, the 

 other through the Octopoda to Octopus and Eledune. The former is 

 principally effected by changes in size, without any chauge from the 

 original position. Compared with Enoploteuthis and Sepioteuthis it is 

 much longer in Ommaslrephes, Loligo, and OnychoteutJiis ; others have 

 a rudimentary efferent duct. In Chiroteuthis Veranzi it is triangular 

 in form ; in Sepiola it is trilobate. It is in Sepia only that this ink- 

 bag becomes connected by a long efferent duct with the anus. In the 

 Octopoda change of position is the first point that we note ; the ink- 

 bag tends to pass dorsally behind the diaphragm, and to enter into 

 closer topographical relations with the liver. In Trcinoctopus carence 

 it is smaller, and the duct is shorter than in T. violaceus. The heart 

 of the Myopsida appears to be a further development of that of the 

 CEgopsida, while the still more highly differentiated organ of the 

 Octopoda is evidently related to that of the Myopsida ; no certain 

 comparison can be made with Nautilus or Spirilla. 



Little or no assistance is given by the male generative organs 

 to the resolution of phylogenetic questions ; great differences, suffi- 



