103 



HARDWICKE'S SCIENCE- GOSSIP. 



on " the Geological Relations of the existing Fauna 

 and Flora of the Britisli Isles," published in 1S46, 

 and considered that the great bulk of our species of 

 insects have been derived from Central Europe, as 

 there is not a species which is universally distributed 

 in these islands which is not equally so in Germany, 

 but that traces still exist of several more ancient 

 favmas and floras which are now confined to small 

 and separate areas. 



Forbes argued for the existence of four such sub- 

 floras as, 



1. A Mediterranean flora in the West of Ireland, 

 derived from Spain, overj laud which we must 

 suppose formerly bridged the gulf of 700 miles 

 which now separates Ireland from the Iberian 

 peninsula. 



2. The flora of the mountain-tops of Scotland, 

 Cumberland, Wales, and the North-west of Ireland, 

 derived from Scandinavia and Iceland, supposed 

 to have reached our shores, either by means of 

 icebergs or over land, of which the Orkney, Shet- 

 land, and Faroe islands are the last remains above 

 water. 



3. A Kentish or Chalk Flora. 



4. A Norman Flora, confined to South-western 

 England and South-eastern Ireland. 



Mr. Birchall suggested that the following species, 

 several of which occur in the utmost profusion in 

 the district of Western Ireland, where the peculiar 

 Spanish flora is found, and are scarce r,r non- 

 existent outside that very limited area, are remnants 

 of the old Peninsular or Mediterranean fauna : — 

 Zygcena nubigena, Erastria argentula, E. fuscula, 

 lAthosia caniola, Dianthacia nisus, D. cassia, and 

 Notodoiita bicolor. He exhibited a number of 

 lepidoptera from the mountain regions of England, 

 Scotland, and Ireland, and was of opinion that 

 such species as Crymodes exulis, Zygcena exulans, 

 Pachnobia alpina, Psodos trepidaria. Anuria cor- 

 digera, A. melanopa, and many others, had certainly 

 reached our shores from Scandinavia and Iceland. 

 As regards Forbes's 3rd and 4th subdivisions, he 

 did not think any evidence was to be obtained by a 

 consideration of the Lepidoptera inhabiting the 

 districts in question. There was, no doubt, a general 

 similarity in the species found on the opposite sides 

 of the English Channel, and there are a few con- 

 spicuous insects, probably of French origin, which 

 do not wander far from our southern coast, but 

 there seems no reason to assign a remote date for 

 the naturalization of such insects as Sphinx nerii, 

 Deilephila euphorbia, Plusia orichalcea, Phlogo- 

 phora empyrea, Pieris daplidice, and Argynnis 

 lathonia, which possess powers of flight sufiicieut 

 at any time to enable them to cross the " silver 

 streak." 



Mr. Birchall also exhibited a large number of 

 British Lepidoptera, contrasted with Continental 

 examples of the same species, and pointed out that 



variation from the Continental (or what may be 

 considered the original) type was so great, that in 

 a large proportion of our species it is easy to say at 

 a glance whether the specimen was British or 

 foreign ; thus indicating that the lapse of time 

 since the migration or insulation took place has 

 been sufficiently long to allow of great changes of 

 form and colour, in many cases amounting to what 

 we can scarcely refuse to call the development of a 

 new species. 



Specimens from the Isle of Man appeared to 

 indicate that insular conditions have there operated 

 with exceptional force. 



Corsican and Sardinian Lepidoptera were also 

 compared with Continental examples of the same 

 insects, and were found to vary from the original 

 types, still more than British insects do ; thus 

 probably indicating a longer period of isolation. 



Specimens were also shown of Nonagria concolor, 

 Noctica subrosea, and Bianthcecia Barrettii, the only 

 three British micro-lepidoptera not known to have 

 occurred on the Continent of Europe. 



COMPARATIVE SIZE OF ANIMAL HAIRS. 



npHE hairs of animals are frequent subjects of 

 -■- interest to microscopists, and are figured in 

 many of the popular handbooks. It is curious also 



Fie. {J4. Hair of Seal x 120. 



to study their comparative sizes and proportions ; 

 and as I do not remember to have seen them thus 



rig. 65. Section of Hair of Peccary x 120. 



noticed, perhaps the following sketches taken under 

 the camera may interest some of your readers. 



