[A51]

Sep. 18. 1865 Nothing more wonderful (Transitions) than the Hectocotylus in Argonauta & Tremoctopus, thought to be a parasite, a separated arm of the male which lives independently. No step towards any transition was known until Steenstrup (trans. in Annals & Mag of Nat. Hist. (2nd series) vol. 20. 1857 p. 81) shewed that in the Cephalopod decapods, one of the arms in the male was modified, & that in the male Octopods the same arm which forms the the Hectocotylus in the above genera is greatly modified or as Streenstrup expresses it is hectocotylized: it terminates in a grasping plate & has a channel for the spermatophores

[Japetus Steenstrup. 1857. Hectocotylus-formation in Argonauta and Tremoctopus explained by observations on similar formations in the Cephalopoda in general. Annals and magazine of natural history, vol. 20, series 2, no. 116 (August): 81-114.]

[A51v]

In the Decapod & Octopod these modified arms are evidently used for copulation & transference of the spermatophores to different parts of the female

[A52]

Steenstrup attempts to shew how each part is homologous with that of the true Hectocotylus. It deserves notice that in the Octopods a torn off arm grows again. (mem. Queen Bee & drone). Steenstrup concludes (p. 106) that the hectocotylus formation "is a far less paradoxical formation than it was supposed to be by naturalists, nor does it occur so suddenly & without transitions as appeared at first. We see rather that the peculiarity, so strange & anomalous at the first glance, is here, as throughout nature, prepared & brought about by a series of transitions." He adds a note that he has some where discussed the breeding of frogs & toads "in which the care of the male of Alytes obstetricians for the eggs, evidently originates from, or is in relation with, the obstetric assistance which all the species render to their females."