PROGRESS OF MICROSCOPICAL SCIENCE. 
39 
dosteus, in greater complexity at the base of the teeth of Varanus, and 
in exceeding complexity in the teeth of Labyrinthodonts. 
The author would distinguish, therefore : 
(i) Hard unvascular dentine, the characters of which are suffi- 
ciently known. 
(ii) Vaso-dentine, which is developed from odontoblasts after the 
manner of dentine, but contains an anastomosing network of 
canals modelled around and containing capillaries. 
(iii) Plici-dentine, developed from odontoblasts, but from a com- 
plicated pulp, so that it is more or less divided up into 
distinct systems of dentinal tubes. 
(iv) Osteo-dentine, developed from osteoblasts, like bone, and quite 
unlike dentine ; permeated by a system of large canals, which 
do not contain, or have any special relation to, blood-vessels. 
The author lays no stress on the characters formerly given as dis- 
tinctive of osteo-dentine (i. e. a laminated arrangement of the matrix 
and the presence of lacunse), because (i) lamination of the matrix is 
not unknown in vaso-dentine, (ii) lacunae are very frequently absent 
from hone in fishes, and very frequently from osteo-dentine, so that 
these characters, as those who have tried to apply them have found, 
are not useful in practice. The attachment of the teeth of the hake is 
so peculiar as to merit a word of notice : the inner and longer of the 
two rows of teeth are set upon elastic hinges, which allow of their 
being bent inwards towards the throat, but cause them at once to 
spring back into the upright position when pressure is taken off them. 
This arrangement, shared by the angler, was hardly to be expected in 
one of the Gadidac ; but the author has found in others of the family 
steps toward this highly specialized arrangement, the benefit of which 
to a voracious predatory fish like the hake is obvious.* 
The Microscopic Study of Human Blood . — The ‘Medical Examiner’ 
(May 31) says that the Medical and Surgical Society of Bordeaux offer 
a prize of 1000 francs, to be adjudged at the end of the year 1879, for 
the best essay on the following subject : — The microscopic study of 
human blood, recent and dry, of the foetus and adult, compared with 
that of the blood of other mammals, from a medico-legal point of view. 
The essays must be very legibly written in French or Latin, and ad- 
dressed, post-paid, to M. Donaud, Secretaire General de la Societe, 
Allee de Tourny, 10. The last day for the essays to be received will 
be the 31st of August, 1879. Each essay must bear a motto, and be 
accompanied by a sealed envelope containing the name and address of 
the author, or of his agent. 
Fungi in Excrement. — Dr. Trimen states, in the ‘Journal of Botany’ 
(June 1877), that these have lately been investigated by M. E. C. 
Hansen. A memoir has been written by this author which compre- 
hends an account of the fungi found in Denmark growing on excre- 
ment, and is chiefly devoted to their classification, literature, and 
geographical distribution, but there are also various morphological 
* Sec ‘Proc. Koy. Soc.,’ No. 179. 
