18 MR. W. H. FLOWER ON THE BRAIN OF THE ECHIDNA. [Jan. 26, 
January 26, 1864. 
E. W. H. Holdsworth, Esq., F.Z.S., in the Chair. 
Mr. Monteiro exhibited a living Pigeon (Columba arquatrix), ob- 
tained by his son Mr. J. J. Monteiro nm Benguela. 
An extract was read of a letter from Dr. Harry Anthony to Mr. 
Louis Fraser, dated Brass River, Bight of Biafra, 3rd Dec. 1863, 
referring (as follows) to what was supposed to be a species of Cla- 
rLas :— 
«TI intend to try and send you by my next ship some of the ‘ Black 
Fish’ out of the bush, called by the natives Egalegala; they are 
perfectly black, and are very fine eating. They are so fat they will 
fry without butter, taste something like eels; they are in shape 
something like ‘ Catfish,’ with filaments from the lower jaw ; they 
live amongst the mud in the mangrove bush. It would be grand 
to acclimatize them ; they are such fine eating. They would drive 
eels out of the market. 
The following papers were read :— 
1. On THE Optic Lopes or THE BRaIN OP THE Ecuipna. By 
W. H. Frower, F.R.C.S., F.Z.S., ConservaTOR OF THE 
Museum or THE Roya COLLEGE OF SURGEONS. 
It is commonly stated in works on comparative anatomy, that 
while the optic lobes of the Mammalia generally are ‘‘ corpora qua- 
drigemina,”’ in the Monotremata they are “‘ corpora bigemina;” and 
herein a transitional character towards the inferior vertebrates has 
been perceived. 
Professor Owen’s description of these parts, in the article ‘‘ Mono- 
tremata”’ in the ‘Cyclopedia of Anatomy and Physiology’ (the 
standard original authority upon the anatomy of this group of ani- 
mals), runs thus :—In the Ornithorhynchus “ the posterior bigeminal 
body is much smaller than the anterior, and the transverse depression 
which divides them is very feebly marked: the longitudinal groove 
is equally feeble on the ‘nates,’ and is altogether absent in the 
‘ testes,’ which thus form a single small tubercle. It is in the con- 
dition of these parts, recognized, but too briefly noticed, by Meckel, 
that the brain of the Ornithorhynchus deviates most essentially from 
the Marsupialia, and offers the most direct step in the descent to the 
Oviparous type.” Of the Echidna he says, “The optic thalami and 
nates appear as one convex body, slightly contracted laterally, and 
divided from each other by a sigmoid linear fissure: the testes are 
only half the breadth of the nates, and the median longitudinal line 
of division, which is very faint in the larger bodies, is not visible in 
the small and posterior tubercle. The Hehidna corresponds in this 
characteristic modification with the Ornithorhynchus.” 
