8o NATURAL SCIENCE. July, 1894. 



It may also be pointed out that Mr. Willis's general conclusion, at the bottom 

 of p. 350, implies the inheritance of acquired characters. External causes, he says, 

 produce various degrees of sexual development, on which " Natural Selection only 

 begins to act later on." But Natural Selection, we are told, can only act on cha- 

 racters that are congenital. Does Mr. Willis appreciate the importance of his own 

 conclusion, and what has he to say to this interpretation of it ? 



Entomophilos. 



The Hatching of the Octopus. 



Miss Agnes Crane writes expressing astonishment at the ignorance displayed 

 in our notes on the octopus in last month's " Notes and Comments." She says ; — 



" As a matter of fact the ' brooding ' of the ' hen ' octopus and the hatching of the 

 eggs was a fifty days' wonder at the Brighton Aquarium many years ago, and the 

 subject of general comment in the daily and weekly Press. I have watched 

 the female often hovering over the two dozen or more live oysters she had sedulously 

 accumulated in a rocky crevice of her tank near the glass for weeks together. P'uU 

 descriptions appeared in the Times, Land and Water, The Field, etc., at the time, and 

 Mr. Henry Lee subsequently devoted a whole chapter to ' The Spawning of the 

 Octopus,' recording his observations in his ' Aquarium Notes ' on ' The Octopus of 

 Fiction and the Octopus of Fact,' published by Chapman and Hall in 1875. 



" Therein he relates that the female octopus deposits her eggs, ' which look like 

 little grains of rice,' in strings, at intervals, for three days, a fair-sized specimen 

 producing ten or twelve long strings, or clusters, or a possible progeny of from forty 

 to fifty thousand individuals, that she broods over them, guards them, and 

 cleanses them, taking but little food the while, and becoming quite exhausted by her 

 maternal cares. 



" Moreover, your contributor used the word ' incubation ' loosely, and seemed 

 to imply that the octopus sits upon its eggs for the purpose of hatching them by 

 the heat of her body. Mr. Lee held this theory not proven, as he succeeded in 

 hatching out a brood of several hundred young octopods from ova which had been 

 removed from the mother in question and placed in a tank by themselves. 



" Young octopods are described ' as almost as big as a flea, and, when irritated, 

 of much the same colour,' and as able to assimilate their hue to the colour of their 

 surroundings even before they have left the envelope. The brood referred to lived 

 about three weeks, but ultimately succumbed, possibly to the over-assiduous 

 attentions of their scientific dry nurses : at that time Mr. Frank Buckland, Mr. 

 Henry Lee, and Mr. W. Saville Kent were all professionally attached to the Institu- 

 tion. The eggs of the Sepia and of Loligo were also hatched out independently at 

 the Aquarium when removed from parental care. The octopus, therefore, probably 

 guards, cares for, and hatches her eggs just as the nest-building ' fifteen-spined ' 

 sticklebacks do, and not in the usual sense of the word incubation. Mr. Lee stated 

 ' that octopods he had known ' differed much in their manner of ' brooding ' over 

 their eggs. He also recorded the occurrence of a full-grown female octopus and her 

 eggs within an earthen two-gallon carboy which had been dredged in the channel, 

 and of which the neck measured only two inches in diameter. But I have said more 

 than enough to prove that the ' hatching of the octopus ' has not been forgotten 

 since the days of Aristotle. 



[We protest against the assumption that " incubation " involves heat. The 

 term actually was applied to fish by Owen. — Ed.] 



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