1889.] ANATOMY OF GONATUS FABRICII. 131 



surfaces of the pads. This idea is supported by the observations 

 that in some sections the pads could be seen firmly pressed together 

 with a thin line of structureless material between them. The fusi- 

 form or rod-like bodies within the cells might be compared witli the 

 structures found in those cells of Cercaria which secrete the cyst 

 (cellules a batonnet) \ 



The suggestion just made with regard to the function of thefuimel- 

 organ is by no means free from difficuUies. Of tliese the most serious 

 is that it persists in the adults of those forms which have a well- 

 developed valve in the siphon. Its discharging one function in 

 the embryo is not necessarily, however, a bar to its having some 

 different use in the adult. 



Tlie objection that in those embryos in which it is well formed 

 (Sepia, Loliffo) there is a valve in the funnel, may be answered by 

 the hypothesis that in these small animals the valve is inadeqnate. 

 I have seen some sections of Sepia in which the valve would cer- 

 tainl)' be quite insufficient to close the lumen of the funnel, unless 

 this latter were to contract very considerably by its own proper 

 musculature. 



Another weighty argument which may be raised is, that this 

 seems a circuitous mode of obtaining the end desired, that if a valve 

 is to be developed it would be best to have it ready for use by the 

 time the embryo quits the egg. Nothing in the way of proof can be 

 urged against this, but it may be remarked that natural processes 

 often seem to us at first sight to be very roundabout in their way of 

 operation. The whole subject is well worthy the attention of any 

 observer who has the opportunity of working it out more thoroughly 

 on fresh material. 



XII. General Conclusions. 



The information now in our hands for instituting a comparison 

 between Gonatus and its nearest allies Onychoteuthis and Enoplo- 

 teuthis may perhaps be most conveniently summed up in the form 

 of a table. For a number of facts regarding the latter two genera, 

 which I have not had an opportunity of verifying for myself, I 

 must acknowledge my indebtedness to the thesis of my friend 

 Dr. Brock '. 



' Sonsino, " Celhiles a batonn. de cert. Cercaires," Arch. ital. Biol. vi. pp. 

 37-61 (1884) ; Thomas, " Life History of the Liver Fluke," Quart. Journ. Micr. 

 Sci. xxiii. p. 127, pi. iii. fig. 20 (1883). 



^ "Phylogenie d. dibrauch. Ceph.," Morph. Jabrb. vi. 1880. 



