522 Chronicles of Science. [July, 



The appearances can be explained on the supposition that some animal 

 crawling on the soft mud at the bottom of shallow water, by means of 

 feet which made a double series of transverse marks, was in the habit 

 of excavating deep burrows for shelter or repose. The burrowing of 

 the modern Limulus would produce a similar effect, with the addition, 

 however, of the mark of the caudal spine, of which these fossils show 

 no trace. Hence the animal required would be a crustacean, having 

 feet and habits of life generally resembling those of Limulus, but 

 without a caudal spine. Such were trilobites ; and in particular the 

 feet of Asaphus, as discovered by Mr. Billings, would appear to be 

 precisely what would produce the markings. Dr. Dawson thinks it 

 probable that the burrows were places of incubation, and that the 

 tribolites carried their spawn attached to their swimming feet, and 

 were in the habit of resorting to shallow water for the purpose of 

 incubation. He proposes to change the generic name to Busich- 

 nites ; and he thinks it probable that the Grenville specimens may 

 belong to three species of tribolites. Similar fossils from the 

 Lower Carboniferous of Nova Scotia are named JR. Carbonarius. 

 Lastly a species from Cape Breton, called It. Acadicus (figured in the 

 ' Canadian Naturalist ' for December, 1864), seems to be the track of 

 the swimming feet and edges of the carapace of a small Limulus. 



The second paper was by Mr. Billings, " On a remarkable speci- 

 men of Asaphus platycephalus." The author exhibited a specimen of 

 this tribolite from the Trenton Limestone of Ottawa, which had been 

 in part carefully extricated from the matrix. The specimen had eight 

 thoracic segments, and exhibited on the under side eight semi-cylin- 

 drical ridges on each side of the median line, all curving outwards and 

 forwards. Mr. Billings believed these to be the bases of attachment 

 of eight pairs of swimming feet. Burmeister's supposition as to the 

 nature of the legs of tribolites was fully borne out by this discovery, 

 except that in Burmeister's sketch the limbs are directed backwards. 

 The legs were probably thin and foliaceous. 



Apatite (phosphate of lime), according to a paper by Dr. T. S. 

 Hunt, occurs abundantly in several parts of Canada, as in the vicinity 

 of Perth, and at several points along the Ottawa. It is found dis- 

 seminated in small crystals through Lawrentian crystalline limestones, 

 and in regular veins which intersect the rocks of the same system. In 

 the latter case it is sometimes nearly pure ; at other times it is associated 

 with pyroxene, large crystals of magnesian mica (which are wrought), 

 and other silicated minerals. Attempts are now being made to work 

 the deposits of this mineral in North Burgess. 



Zoology. — Classification. — An important paper by Dr. Dawson " On 

 the Classification of Animals," appears in the ' Canadian Naturalist.' It 

 is difficult in a few words to give a summary of the views of the author, 

 but the following are some of the salient points : — First, with regard 

 to species. The essential characters of a species are points of struc- 

 ture, proportion of parts, ornamentation and habits ; but it is also 

 necessary to take into account its continued existence in time, and we 

 are therefore brought to the definition of species long ago proposed by 



