Microscopical Society. 1805 



Occurrence of MacropUa Equiseli near Cambridge. — A specimen of this rare in- 

 sect was brought to me a few weeks ago, collected from the refuse which was washed 

 up during a late flood. It had but just attained the imago state, and, when found, 

 had not even emerged from the cocoon. Nevertheless, it was on the very point of do- 

 ing so, for on breaking it open, by mistake, outwalked Macroplea, perfect and mature. 

 Professor Henslow informs me that he formerly captured a pair in the river Cam, 

 about two miles from Cambridge, which are now, I believe, in the possession of the 

 Rev. Leonard Jenyus. I have heard the opinion more than once expressed, that the 

 present insect is not distinct from Zosterae. But this can scarcely be correct, the ap- 

 pearance of the two species being in every respect dissimilar. Not to mention less 

 obvious distinctions, — the larger size of Equiseti, more robust form, and dark tips of 

 the thighs and tibiae, at once afford characters, which, when seen, cannot possibly be 

 mistaken. — T. Vernon Wollaston ; Jesus College, Cambridge, May 3rd, 1847. 



Capture of Pissodes Pini at Gosforth, Northumberland. — Within the last few days 

 I have captured a fine series of this rare insect. On the 24th of May, I made a short 

 excursion to Gosforth Woods ; and noticing some stumps of Scotch fir (Pinus sylves- 

 tris), I was led to examine them, in hopes of finding some old favourites, (Ips, Sec). 

 In this I was disappointed ; but a search of the branches and chips of the same tree, 

 which were lying on the grass, was rewarded with ten specimens of Pissodes Pini, liv- 

 ing in apparent harmony with the hundreds of Hylobius Abietis inhabiting the same 

 situation. A few days later I again visited the locality, with tolerable success, adding 

 a few interesting varieties to my collection, also meeting with a pair of Ips fer- 

 ruginea. — Thomas John Bold; 42, Bigg Market, Newcastle-upon-Tyne, June 

 8th, 1847. 



Report of the Microscopical Society of London. 



May 19th, 1847.— J. S. Bowerbank, Esq., F.R.S., President, in the Chair. 



A paper by John Quekett, Esq., 'On the minute arrangement of the Capil- 

 laries in the respiratory organs of Fishes' was read. The author, after describing 

 briefly the structure and arrangement of capillaries generally, stated that, it was to 

 the microscope that we were mainly indebted for what was known of the capillaries 

 and of the capillary circulation ; he then alluded to the large size of the capillaries in 

 the Reptilia, and to their minuteness in the gills of fishes, these last he purposed to 

 consider more in detail. In osseous fish, he stated there were four gills on each side, 

 supported on long, curved, branchial arches. Each gill, consisted either of a single 

 or double series of lancet-shaped filaments attached to the branchial arch like the teeth 

 of a comb. In some animals these filaments or lamellae, as they have been termed, 

 were united at their bases, and upon them the respiratory mucous membrane was won- 

 derfully plicated, the plicae lying always in a direction at right angles to the lamella. 

 The arteries which bring the impure blood to the gills run along the convex borders of 

 the branchial arch, whilst the vein ran in the opposite direction. Each artery gave 

 off as many branches as there were lamellae, the branches divided twice, and then ran 

 along one edge of the plicae of mucous membrane on the lamellae, and the vein on the 

 opposite edge and between these vessels was the most minute plexus of capillaries ever 

 yet described: they formed a delicate hexagonal net-work precisely analogous to that 



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