74 



HARD WICKE'S SCIENCE- G OSS IF. 



show themselves first on the last (the outer) whorl 

 of the shell — as in living animals, e.g. in my lizards 

 at the tail — and that then such a change in the 

 following generations is pushed farther and farther 

 towards the beginning of the spiral — as e.g. in my 

 lizards towards the head — until it prevails in the 

 greater number of the whorls" ("Organic Evolu- 

 tion," p. 31). This may explain the coloured nuclei 

 of If. maritima and H. syriaca, but I cannot say 

 anything of these as I have not any specimens of 

 these species by me. And if there be sucli a law of 

 after-colour extension, as suggested by Eimer, the 

 reader will see that it has other bearings on my theory 

 than the one here indicated. 



(3.) Mr. Fryer, while recognising the fact that the 

 Limnaeas are horn-coloured, mentions the banded 

 and spotted Chilinire, and the members of the families 

 Paludinidas, Neritidce, Cerithiadre, &c. With these 

 exceptions other conditions I imagine come into play, 

 but it is a patent fact that in all of them the young 

 secondary shell is horn-coloured and unhanded. 

 What these other conditions are is not known, but 

 it is a pity that those exceptions which Mr. Fryer 

 adduces are in the main foreign and cannot be 

 observed by us in their natural and living state under 

 their own peculiar environment or surrounding. 

 Considering the fact italicised by me and remem- 

 bering Hffickel's law, I cannot see how this criticism 

 can invalidate my theory. 



(4.) The fact that white " may be due to the 

 molecular structure of the surface " rather, it appears 

 to me, upholds and substantiates my theory. Mr. 

 Fryer would not then allow a unicoloured white 

 specimen any pigment secreting cells at all, that is on 

 the grounds of theoretical reasoning ; more of this 

 deduction shortly. But if the primitive shell was 

 horn-coloured, as he appears to admit, but that an 

 advance to white was not next made, how does he 

 explain the fact that the primary shells in the shell- 

 gland are sometimes white, though more generally 

 horn-coloured, and that the persistent primary shell 

 in Arion, Amalia and Limax is always white ? 

 Remember in this connection the law of Hceckel, 

 and do not forget it in re-reading the query which 

 Mr. Fryer gives directly afterwards. But what does 

 Mr. Fryer mean by atrophy of the pigment glands in 

 this relation ? Does he really mean that nature 

 finds it easier to differentiate cells than to let them 

 remain hi statu quo ? It appears to me, that con- 

 sidering the ontogeny of the shell was from horn- 

 colour to white, pigment-secreting cells were only 

 differentiated when pigment was needed, that during 

 the horn and the white periods pigment cells were 

 not in existence, and had never been developed. 



(6.) I cannot see how the criticism affects my 

 theory. If its " light appearance seems to be due to 

 the absence of band-colour," etc., as most assuredly 

 it does, or it would not be var. cxalbiday then why 

 may it not be a " reversion " ? 



(7.) Answered in my reply to Mr. Pace. 



In his concluding remarks, ISlx. Fryer leans 

 towards the suggestion of Mr. Cockerell that the 

 colour of our Hyalinse is probably due to the 

 suffusion of darker band colours. But if so, banded 

 reversions would occur not only in one but in all the 

 species, and this is known not to be the case. The 

 question of tf. cantiana, H. caiiicsiana, &c., as 

 equally and more legitimately (I think) supports the 

 opposite conclusion to that at which Mr. Fryer 

 seems to arrive. I look upon banded specimens as 

 more advanced in colour development than those 

 which are unhanded. Banding means a specialisation 

 of pigment-secreting cells in the mantle edge. And 

 were Mr. Fryer's remark true, the bands in this case 

 of Hyalina should be lighter than the ground-colour ; 

 but in the varieties he adduces, they are darker ! 



(i.) Answered by ontological facts, von Baer's 

 law, and the law of Hseckel. 



(ii.) This is more an extension of my theory than 

 a contradiction. It shows that, in some cases, un- 

 colourous specimens may be produced by an inter- 

 mingling of bands, though ontology negatives this 

 for horn-coloured and white specimens. Evidently 

 castanea is an advance on the clearly banded forms of 

 II. ucmoralis. 



(iii.) I cannot see how these observations, inter- 

 esting in their way, affect my general theory. Again 

 I stand behind the fortress of Von Baer and Ha;ckel, 

 and to those who understand the full bent of the laws 

 which were formulated by them it will appear that I 

 shall not use much powder and shot. 



(iv.) This also becomes intelligible in the light of 

 the development of the shell. And I think more 

 legitimately. What, again, I ask about the horn- 

 coloured and whitish primary shells of the embryo, 

 and the persistent ones in Arion, Amalia, and 

 Limax ? 



(v.) Replied to in my answer to Mr. Pace. But 

 Helix aadeata and H. pygmca are horn-coloured 

 also ! But besides what I have before said, what 

 Mr. Fryer adduces as regards shrews and ants rests 

 on probability and not actual observation. See the 

 references which he gives. 



" BIRDS OF THE WEST." 



A FEW notes on birds observed by me, in the 

 west of Co. Mayo, during the months of August 

 and September, may be of interest to some of your 

 readers. I saw no particularly uncommon ones : in 

 fact, my observations merely comprise the results of 

 a few desultory walks from time to time, most of 

 my attention being occupied with fishing. 



At the beginning of August, on the sandy sea 

 coast, golden plovers were in some numbers and 

 very tame : grey plovers did not seem to have 

 arrived yet ; dunlins also were. exceedingly plentiful ; 

 they breed in the neighbourhood. Curlews and 



