PROCEEDINGS OF SCIENTIFIC SOCIETIES. 197 



disease similar to diphtheria, and said to be fatal to cattle. Isaria fre- 

 quently grows on animal substances, dead and living, as on larvae and pupae 

 of ichneumons, spiders, moths, wasps, &c. 



Mr. Smith showed a bee caught alive in this country, and having a 

 profuse growth of the Isaria condition of the Cordiceps sphecocephala, a 

 W. Indian form, the latter genus being closely allied to Clavieps, or Ergot. 



Dr. Francis Day read a paper upon the Salmones found in the British 

 Isles, remaking how great changes are occasioned by retaining any of them 

 in unsuitable localities. He objected to the augmentation in number of the 

 British forms of non-migratory Trout from three to seven, as made by 

 Dr. Gunther, holding that we possess only two : — the Loch Leven Trout, 

 which is in reality a marine form acclimatized to fresh water, whereas the 

 remainder are solely local races of the common Brook Trout. A most 

 interesting fact was brought forward, viz. that Mr. Arthur, in New Zealand, 

 having lately examined the Trout which were introduced there in 1869, 

 from ova originally obtained from the Thames and the West of England, 

 found great structural changes had taken place. The fish in question, 

 moreover, living in different streams in New Zealand, had also assumed 

 local peculiarities of size and change of form ; and, due doubtless to increased 

 food, the annual increment of weight had risen from Is to 2£ pounds, and 

 an example had been seen weighing 20 pounds. The ccecal appendages, 

 hitherto held as significant of species, were found augmented from 83 to 50, 

 as exemplified in British fish, to from 43 to 54 in the New Zealand 

 examples, showing that these organs are inconstant in number. Having 

 alluded to the different species, Dr. Day concluded that, as the various 

 species of non-migratory Trout, accepted by Dr. Gunther, interbreed, 

 and the hybrids are not sterile, the fact gives increased reason for sup- 

 posing these various forms are merely local races, and not different 

 species ; that if they are really distinct species, division has not proceeded 

 sufficiently far, because the Gillaroo, a form of Trout with a thickened 

 middle coat of the stomach, has been termed Salmo stomachicus, Gunther, 

 whereas the Great Lake Trout with a thickened stomach, and the Charr, 

 having a similarly transformed organ, have not yet been differentiated into 

 species. Dr. Day considers that all our non-migratory freshwater Trout 

 (excluding the Loch Leveu) are merely local races ; that interbreeding will 

 produce mongrels, in which sterility need not be anticipated, while intro- 

 ducing new races (unless on the principle of preventing breeding in and in) 

 will not be of much benefit to fisheries, unless the food is in excess of local 

 requirements, for if not the new-comers will revert to the colour, form, and 

 size of the original tenants of the water. 



Two papers by Mr. Charles Darwin — (1) on the action of carbonate of 

 ammonia on the roots of certain plants, and (2) the influence of carbonate 

 of ammonia on chlorophyll bodies — were read. The observations which led 



