Transactions. 107 



Other points arise in the study of these numerous but easily 

 passed over creatures. For instance, I am fond of thinking that 

 it is only to cloak our laziness and ignorance that we divide and 

 sub-divide Creation into orders and genera and species. There 

 are always, if not in our own Flora and Fauna, then in some 

 other, links between one genus and another ; and, if we only 

 knew more, we should readily admit that really there is no such 

 thing as " species," or, rather that what we call a " species" is 

 only the outcome at one particular epoch, a climax, of innumer- 

 able gradations in forms of being. It is doubly interesting, 

 therefore, to be able to fill up an admitted gap in tlie natural 

 sequence. By finding, for the first time in Kirkcudbright, this 

 little shell, Valvata cristata, one day amid hosts of Planorbis 

 albus on the floating pondweed-leaves, one of these links was 

 made clear to me. V. cristata, not only by internal organisation, 

 but by shape of shell, connects most palpably the Genus Planorbis 

 with the Genus Valvata. Planorbis has a flat discoid shell, in 

 many species perceptibly convex, indeed, on both sides. Compare 

 one of them with the commoner Valvata (V. piscinalis) of our 

 Fauna, and see the difierence. Then note how neatly and 

 timeously this tiny cristata comes in to blend the two genera, 

 witli its shell, as Gwyn Jeflery remarks, " perfectly flat in all 

 stages of growth " — so like a Planorbis albus, and yet so unmis- 

 takably a Valvata in texture and colour, and those more subtle 

 distinctions which make the real difiiculties of science. In the 

 same way Physa acuta, a European species, connects our two 

 species of Physa, hypnorum and fontinalis ; and another sliell, 

 whicli we ought to get in our district, Zonites fulvas is tlie link 

 between the true Zonites and tlie true Helicidae. I might 

 multiply instances of this kind ; but as this is not a lecture upon 

 Malacology, I must refrain. My object is merely to suggest the 

 direction in which many of us might find plenty of work and 

 study on taking up the subject of mollusks and shells. I repeat, 

 in conclusion, that, in addition to the liealtliful pursuit of 

 watching and hunting for these strange little creatures, there are 

 no obstacles such as expensive tools or accessories of any kind in 

 the path of the adventurer. Even time is not so much a desider- 

 atum as in almost any other Natural History pursuit. Some 

 scores of pill boxes of various sizes, an old mustard tin or two, a 

 long stick to which a salmon gafl" or a bag-net can be quickly 

 fitted, and, I must add, a passion for dabbling in cool, clear- 



