HA RD WI CKE'S SCIENCE- G OSSIP. 



27 



was described from one specimen, and is, I think, an 

 individual monstrosity ; very likely other specimens 

 will occasionally be found, as is usually the case with 

 such forms. The same remarks apply to Limncea 

 glutinosa, var. intorta. 



34. Limncea stagnalis, var. speciosa, which is 

 omitted, is a very distinct-looking variety. 



35. L. stagnalis, var. elegantida, is omitted, though 

 it is a very remarkable little variety. My brother 

 and I noticed that one year, when the pond con- 

 taining them increased in size from abundant rains, 

 the elegantttla came to resemble more the forms found 

 in neighbouring ponds ; but nevertheless, the variety 

 seems distinct, and I have never seen anything that 

 could be confounded with it, except perhaps the var. 

 minima, of which I saw only one example. The 

 var. minima, found at Milford, Yorks, by Mr. Geo. 

 Roberts, is lo\ mill, long, 9 mill, diam., whorls 6, 

 spire slender, aperture oblong, inner lip thickened. 

 It has, I believe, the same relation to stagnalis 

 proper that elegantida has to var. lacustris. 



The variety bottnica, Cless., is included in the 

 list, and I believe Mr. Taylor considers elegantida 

 identical with it. But certainly the two must have 

 had an independent origin, and var. bottnica belongs 

 to the section in which the shell is clear horn-colour 

 or whitish — very different from elegantida, which is 

 dark brown, and differs also from the usual forms 

 in the colour of the animal. 



36. L. stagnalis, var. expansa, is omitted, no doubt 

 being included in var. lacustris, of which it is a sub- 

 variety. 



37. Z. stagnalis, var. scalariformis, is omitted, 

 although very good specimens have been found. The 

 same may be said of the scalariform Bythinia 

 te7itaculata, of which Mr. Geo. Roberts sent me a 

 specimen from Milford, Yorks. Is it not rather 

 inconsistent to leave these out, when similar forms 

 of other species are included ? 



38. L. stagnalis, var. compressa, is omitted, though 

 it is a distinct variety. I have seen it referred to 

 Roberts' palustrifotmis, but no doubt wrongly, as 

 that is a slender, thin-shelled variety, 40 mill. long. 

 Curiously, Mr. Bryant Walker has just described and 

 figured as new a var. sanctcemarice from Michigan, 

 which appears to be practically the same as com- 

 pressa. Of the two figures he gives, his Fig. 5 

 ("Nautilus," 1892, pi. 1.) most resembles the 

 English specimens. 



39. L. palustris. The forms carina ta, globosa, and 

 turrita, which are omitted, are no doubt individual 

 monstrosities. The var. angulata, also omitted, is 

 not a mere monstrosity, as two or three were found 

 in the same pond, from which I infer that the 

 peculiarity is more or less racial. 



40. Acme lineata. I never had the material to 

 judge of the matter, but it seems certain that we have 

 two forms, perhaps to be known as lineata proper, 

 and fusca, Walk, and Boys, or polita. Captain 



Brown recognised two forms, describing one as Acme 

 minuta, from Lanarkshire. 



41. Vertigo seems at best only a subgenus of Pupa ; 

 there may be some question whether we should not 

 write Pupa vertigo, Mont., instead of P. angustior. 

 There was, however, an earlier Pupa vertigo, Gmei., 

 17SS, which is a synonym of P. pusilla, Mull., 1774. 



42. Bythinia Leachii. Several years ago Mr. Geo. 

 Roberts sent me a ventricose form of this, measuring 

 4 mill, long and 3J broad. It was found by Mr. 

 Hargreaves, in the Bolton Canal, near Manchester. I 

 will not propose a name for it, as it may possibly be 

 var. inflata, Hansen, 1845, of which no description 

 is available to me. 



43. Bythinia tentaculata, var. angulata, is omitted, 

 but it is propably a variation similar in character to 

 Limnaa palustris, var. angulata. Mr. Roberts sent 

 me two specimens, found in the Leeds and Liverpool 

 Canal, Saltaire. In one the angulation appeared to 

 commence at the apex, but the other had the apex 

 normal, the angulation beginning only on the pen- 

 ultimate whorl. 



44. Valvata piscinalis. Why is var. albina, Taylor, 

 left out ? 



45. Pisidium pusillum, var. circidare, which is 

 omitted, is only known from one specimen, taken 

 in Langorse Lake, Breconshire. The typical form 

 also occurred, so it is possible that circidare is an 

 individual aberration, although it seemed a distinct 

 variety. Further research is very desirable, as it is 

 not improbable that the British lakes, if adequately- 

 searched, would produce peculiar races of Pisidiuim 

 as do those of Switzerland. 



46. Pisidium nitidum, var. globosum, was, I believe, 

 originally named in MS. by the late Dr. Gwyn 

 Jeffreys, from specimens taken at Swinton by Mr. T. 

 Rogers. See J. C. Melvill, " Mollusca," (Brit. 

 Assoc. pamphlet), p. 3. 



47. Unio tumidus. There was a very remarkable 

 variety found in Regent's Park, and named richensis. 

 I have seen specimens in the British Museum, and 

 there is an account of it in Mr. Harting's work on 

 shells. Yet nobody appears to have taken it of late 

 years. There are some very similar North American 

 species, and possibly it may have been one of these 

 imported, as it looked very distinct from tumidus. 



The above comments are only a few of the many 

 that might be made, as the subject is full ol debate- 

 able points. Probably much that now appears 

 obscure will be cleared up in the long-promised 

 monograph, and the readers of this journal could, 

 no doubt, throw fresh light on most of the matters 

 above discussed. 



So far from deprecating the increased interest 

 lately shown in "slight varieties," I believe it to be 

 an indication that the time is now passing away, in 

 which systematic zoology is confined to the con- 

 sideration of genera and species ; and that the 

 doctrine of evolution, now fully accepted by the 



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