SCIENCE-GOSSIP. 



opportunity it gives for making the following 

 observations. 



With regard to the number of band variations 

 according to the formulae which are above referred 

 to as having already been observed, the writer 

 mentions only thirty-three. Like " all " who 

 " have at one time or another had a turn at them," 

 I have often noticed these variations casually, but 

 it has only been for the past three seasons that I 

 have given anything like systematic attention to 

 the variation of H. nemoralis and H. hortensis, 

 especially in regard to the band variation and 

 its cause. During that time I have personally 

 found no less than fifty-three different variations of 

 the band formulae in those two species. So far, 

 independently of a small quantity of unsorted 

 material, not at hand as I write, which I 

 believe contains one or two more, the numbers 

 are forty-eight of H. nemoralis and twenty-six 

 of H. hortensis, many forms being common to 

 each species. These I hope to describe in 

 these pages on another occasion, with notes 

 on their relative abundance or scarcity in the 

 localities where I have searched for them. I may 

 here mention, however, to show how much more 

 one species is prone to variation of the formulae, that 

 in bands only, not combinations of bands, I so far 

 find nemoralis has twenty-two forms, and hortensis 

 only eleven, all the latter also occurring in 

 nemoralis. Of combinations of bands by suffusion 

 and otherwise, I have found twenty-nine variations 

 in nemoralis, and fifteen in hortensis. I have three 

 forms in hortensis which have not been found by me 

 in nemoralis. With regard to the relative amount 

 of searching for each species, I have spent about 

 an equal number of hours on each, and examined 

 about equal numbers. 



In reference to the last paragraph above quoted, 

 I may say that as far as has been practicable in 

 the centre of London, I have reared to maturity 

 both species from very young specimens, though 

 not actually from eggs, with some remarkable 

 results. I find I can by change of food and other 

 means alter the band formula of an individual, I 

 think I may say, at will. By that I mean particular 

 bands will suddenly disappear or appear during 

 growth of the shell. These experiments are, how- 

 ever, at present too uncertain to describe without 

 further experience. I believe that in the country, 

 with proper conveniences, much is to be learned by 

 actually breeding the varieties by pairing specimens 

 which have been isolated from birth, up to the time 

 of pairing. My opinion is confirmed by collecting : 

 certain forms occur in certain localities each year 

 and have only as yet been found by me in those 

 localities, though I have worked many others. 



My plan in studying variation as e.xhibited in 

 these two and their allied species — than which 

 there are few animals in this country giving a 



longer range of variation — is to find out as 

 far as possible what does occur in a state of 

 nature, and especially what does not occur. 

 When we arrive at an approximation of the 

 latter fact it will be necessary to enquire into 

 the reason why such is the case. At present 

 no one even seems to have given any sensible 

 reason why these snail -shells have bands at all, 

 better, perhaps, than — like the stripes on a tiger— to 

 help to hide them in the grass. The first difficulty 

 with the theory is, that when the animal is at rest 

 or feeding, with few exceptions the natural posi- 

 tion of the stripes on the shells is across the grass 

 and not in the direction of its growth. 



Sometimes I am asked, " Do you think it possible 

 to get all the eighty-nine different band formulae ? " 

 I can only reply that I think it is, when I have 

 got so large a proportion myself, without outside 

 aid, in three seasons, and without exchanging or 

 gifts from others. My object in having this list 

 printed, was. that I might send it round, for 

 their local census, to the very few people in 

 this country and on the Continent who collect 

 these band forms, so as to try to get at some 

 estimate of the missing forms. While so printing, 

 it struck me that it might also be a label list ; 

 for nothing is more troublesome in this investiga- 

 tion than having to turn out unlabelled series of 

 band forms for reference. 



Nowhere do I claim to be the originator of the 

 band formulae, as seems to be suggested in the note 

 above quoted. I was perfectly acquainted with the 

 article by Sauveur in the " Annals of the Belgian 

 Malacological Society " published in 1867. By the 

 way, our would-be corrector does not seem to know 

 that Sauveur's table quoted was not an original 

 invention, but is an exact copy of one issued by 

 Jules Colbeau, in December, 1S59. The latter is 

 apparently the first full table published setting 

 forth the whole band formulas of these species. 

 Albin Gras, in 1S40, had theoretically worked it out 

 by mathematical methods, and gave sixty-five 

 instances, doubtless knowing the rest. He iden- 

 tified the bands by the vowels a, e, i, 0, u. G. von 

 Martens, in 1S32, appears to have been the first 

 who originated a formula which enables the band 

 variations to be described on paper. We therefore 

 find our " Superior Scientist " as weak in his 

 knowledge of the literature of the subject as of 

 the animals themselves. 



I have had the pleasure of examining IMr. Belt's 

 list, and some others, but have not yet made an 

 exhaustive search into such lists, in view of ascer- 

 taining what additional forms have been recorded. 

 With regard to the list of " varieties," I think I 

 have " saved the mark ! " v.ith H. nemoralis and 

 H. hortensis; for in the three seasons, I have found all 

 of these with one or two exceptions, and many others, 

 including some named by Mr. Cockerell, which 



