XVI 
JOURNAL OF PROCEEDINGS. 
by their heads only. Mr. Spence was in doubt whether the parasite 
belonged to the genus Oxyuris of Rudolphi’s Class Entozoa , or to 
Vibrio of that of the Infusoria of Muller, to which he referred it on 
first discovering it, from its similarity to Vibrio anguilla, which he 
had formerly examined ; but it does not agree with the characters 
of either, and still less with their habitats. Probably it might have 
been separated as a genus from these in the recent work of Ehren- 
berg on these microscopic animals. According to the Dictionnaire 
d'Histoire Naturelle, the species both of Vibrio and Oxyuris have a 
distinct mouth and intestinal canal, neither of which are to be seen 
in these animals, which, consequently, seem to form a distinct, 
though probably closely allied genus. He likewise requested in- 
formation whether Vibrio tritici, figured by Mr. Bauer in the Phi- 
losophical Transactions for 1823, have a mouth and intestines or 
not. 
Mr. Spence likewise stated that the mischief done at Brussels by 
the larvae of Scolytus destructor turned out much more considerable 
than was at first supposed, it having been found necessary to cut 
down fifty or sixty trees on the Boulevards, besides full twenty 
(some of eighty years’ growth, and with the wood perfectly sound) 
in the park, which, for the last three weeks preceding, (with the 
operations of the wood-cutters and sawyers, and fires to burn the 
bark,) had more resembled a German forest than a public garden, 
to the no small wonderment of the promenaders, who came in 
crowds to inquire about the “ betes” denounced by the “ Anglais” 
that had caused all this “ topage.” He had received a profusion 
of acknowledgments from all ranks of the Bruxellois for his exer- 
tions relative to this subject. It now appears, that years ago 
several trees were cut down, which there is no doubt were de- 
stroyed by the Scolyti ; but their decay being attributed to age or 
the soil, a plentiful stock of partially-infected trees were left to 
diffuse the progeny of the occupants around them, as they have 
done very successfully, and the same would in all probability have 
been the case now ; the two or three trees from which the bark 
was beginning to fall would have been condemned to the axe, 
whilst the much greater number, which, although swarming with 
larvae, did not exteriorly show the least symptom of disease, would, 
as before, have been left a fertile nursery for largely propagating 
the malady. Mr. Spence further stated, that M. V. Andonia had 
been studying the habits of the Scolyti very closely, particularly 
S. pygmceus, which had committed dreadful devastation on whole 
forests of oak in France, and had made some new and important 
observations as to the way in which sound trees are brought into 
