468 
NATURE 
[ Sept. 16, 1886 
paper, the chances against it are always very great. Here, then, 
are three objections to Mr. Romane;’ theory which seem to me to 
be weighty and fundamental ; yet he says, in effect, that he 
anticipated, and is prepared to answer, them. This, I must 
say, puzzles me; because in the whole of his lengthy paper, 
occupying seventy-five pages, I cannot find any adequate recog- 
nition of their existence, or any attempt whatever to answer 
them. 
My apology for writing this is that I am shortly leaving Eng- 
land, and wish the readers of NATURE, who may not have seen 
the Fortnightly, to be aware of the character of the objections 
which Mr. Romanes declares that he anticipated, but apparently 
thought of too little importance to require any discussion in his 
paper. ALFRED R. WALLACE 
I AM sorry that I have not succeeded in making my meaning 
clear to Mr. Romanes. I had hoped that my former letter 
(NATURE, September 2, p. 407) would have given some indica- 
tion as to my father’s views. With regard to the sentence 
quoted from the ‘‘ Origin of Species,” our views seem to differ 
so much that it seems u eless to prolong the discussion. 
FRANCIS DARWIN 
Golf Club, Felixstowe, September 13 
I HAVE read the numerous notes and lettersin recent numbers 
of NATURE upon the origin of species and varieties with great 
interest. It seems to me that all your correspondents are raising 
an imaginary difficulty. i 
““Tf it is to the advantage of some particular variety not to 
resemble the parent form,” then that variation must have been 
produced by some efficient cause acting upon the parent form 
alone. Is it not obvious that that cause still acting will be still 
more potent in producing that particular variation when the 
parent form intercrosses with the variety? This is, of course, 
supposing that the new variety is suitable to its environment ; if 
it is not so, no amount of ‘‘ propping up,” whether by 
“famixia ” or otherwise, would perpetuate it. 
If, as is probably the fact, varieties or incipient species have 
arisen from individual divergences, amixia would tend to im- 
mediately suppress them in the case of animals and dicecious 
plants, as a new generation could not possibly arise without 
intercrossing with the parent stock. J. H. A. JENNER 
4, East Street, Lewes 
I SHOULD be glad to call Mr. Romanes’ attention to a letter 
by Mr. Edmund Catchpool, published in Naturr, November 6, 
1884 (vol. xxxi. p. 4), where he will find his theory of physio- 
logical selection very clearly put forward. 
FRANK EVERSHED 
113, Darenth Road, Stamford Hill, N. 
Solution Discussion at the British Association 
If was a pity there was no discussion on solution in British 
Association, Section B, on Thursday last. More than the whole 
day was taken up with reading a great many papers, some of 
them having very little to do with the subject, so no time was 
left for discussion. I was indeed, by the courtesy of the Vice- 
President and the patience of the few remaining listeners, 
allowed to make a few remarks, but of course it was only 
possible for me to indicate that I had something to say. 
In the papers referred to a good deal was said of solution 
being due to purely physical causes. Now this is either a 
truism or a veil to hide ignorance, and I am sure no one was 
a bit the wiser. What we want to get at is THE physical cause 
of solution. Again, a great deal was made of the part 
of the heat of solution that might be accounted for by the con- 
traction in volume of the solution. This looks very learned and 
scientific, and no doubt is interesting from some points of view, 
but even if all the heat could thus be accounted for, it would 
not advance our knowledge of the cause of solution ; it is merely 
surrounding the subject with cobwebs. The question would still 
remain, What is THE physical cause of this contraction ?, and I 
maintain it is due to the affinity of all the elements for one 
another acting as pointed out in my papers on chemical affinity 
and solution published in NATURE, April 29 and July 22 of this 
year. The truth is, chemists, for convenience of study, drew a 
circle and called all within this ‘chemical affinity,” and then 
forgot that the circle was their own making, and imagined it 
was Nature’s work. ‘This restriction has served its day, and 
must now be obliterated if we would understand the plainest 
teaching of the laboratory and make continued progress. 
Portobello, September 9 Wm. DURHAM 
Actinotrocha of the British Coasts 
In NATURE of August 19 (p. 361), which I have only seen” 
to-day, my friend, Mr. J. T. Cunningham, records as a novelty 
the finding in 1883 of Actinotrocha off Cromarty Firth. 
Without giving an exhaustive note of its occurrence off our 
shores since the discovery in 1856 of Phoronis by the late able 
and accomplished Dr. Strethill Wright, viz. one species from 
Ilfracombe, and another on an oyster-shell from the neighbour- 
hood of Inchkeith in the Firth of Forth, the following remarks 
may be of interest. So long ago as 1858 the late Dr. Spencer 
Cobbold found Actinotrocha near Portobello, as was likely after 
Dr. Wright’s discovery, and I have also since met with it inand 
off the Forth. Moreover, at the meeting of the Microscopical 
Society at which Dr. Cobbold read his paper, the lamented 
Dr. Carpenter mentioned that he had found Actinolrocha in 
abundance off the Island of Arran, probably when working at 
Tomopterts and other surface-forms with his friend, the enthusi- 
astic E, Claparéde, of Geneva. Besides these localities, Prof. Kol- 
liker (‘* Kurzer Bericht an der westkiiste von Schottland,” Zeztsch. 
f. w. Zool., Ba. v. 1864) describes the occurrence of a Phoronts 
apparently identical with Dr. Wright’s P. Aippocrepia from Mill- 
port on the larger Cumbrae in the Clyde, a region in which the 
steam-yacht M/edusa from Granton has lately been at work. It 
is probable, indeed, that Pkoronts and its larval form (Actino- 
trocha) are more generally distributed round our shores than 
the scanty notices of them would lead one to suppose. Old 
shells in and off the mouth of the Forth, off the western shores, 
and these and other structures in the littoral region on the 
southern coast of England, as well as the shores of the Channel 
Islands, will probably produce many examples of Phoronts, while 
| the careful scrutiny of the contents of the tow-net in similar 
localities will yield corresponding results as regards Actino- 
trocha. W. C. McInTosH 
St. Andrews Marine Laboratory, August 25 
The Manatee 
I Norice in the review of Dr. C. Hartlaub’s work on the 
Manatees, which appears in your issue of July 8 (p. 214), that 
the geographical range ascribed to that animal on the West 
Coast of Africa has its southern limit at the Quanza. <A refer- 
ence to earlier writers would, I think, justify us in believing that 
the manatee was once to be found as far south as the Cape of 
Good Hope, or else that it has been confounded with the hippo- 
potamus, 
Dapper, in his description of the Cape Settlement, speaks 
both of sea-cows—‘“‘zee-koeien of zee duivels, zoo groot als 
koeien, die bij wijlen te lande gaen weiden ”—and of sea-horses 
—‘‘zee-paerden, een zeer groot en wonderijgelyk zee-gedrocht ” 
(‘‘ Naukenge Beschrijonige der Afrikaensche gewesten,” p. 266 ; 
Amsterdam, 1676). 
Here the hipp>potamus is evidently the see-koe or sea-cow, 
which occasionally feeds on dry land. May not the zee-gedvocht, 
the sea-monster, have been the manatee? 
For Valentyn, also writing of the Cape of Good Hope, refers 
very explicitly to the manatee :-— 
“* Onder de zee dieren telt men de zee koejen, de hier zeer veel 
en ongemeen swaar vallen, alzoo men er zommige van 4 of 5000 
ponden gezien heeft. In West Indien socmt men dit dier Manati 
bij de Indianen, en anderen noemen het wel een Lamantine ; 
hoewel er zijn die beide deze dieren nog eenigzins onderscheiden. 
“« Diergelijk zwaar zee paarden heeft men er ook, hoewel wat 
verder van de Kaap af, gezien. Zij vallen doorgans kastaniebruin ” 
(‘* Beschrijung van Kaap de Goede Hoop,” p. 115 ; Dordrecht 
and Amsterdam, 1726. Eighth volume of ‘‘ Oud en Nieuw Oost 
Indien ” ). 
But here the manatee is called the sea-cow. What is the sea- 
horse (zee-faariden)? Can it be what Leguat saw at sea on his 
voyage from Amsterdam to the Cape —which he reached twelve 
days after the vezcontre ? ae in: 
“Le premier jour de l'an 1691 nous etimes le plaisir de voir 
assez distinctement une vache marine de couleur roussatre (cf. 
the ‘*kastaniebruin” of Valentyn) ‘‘qui faisoit voir la téte entiére, © 
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