Cerebral Tract of Professor Owen. 281. 
correspond, the mouth of the invertebrate being a dewtostome 
and temporary one in the embryo vertebrate (the entry of the 
umbilical vessels forming the primary protostome), whilst the 
mouth of the vertebrate is the final érdtostome. We are not 
informed, however, in what vertebrate embryo such an an- 
terior communication through the palate is actually found ; 
but the inference is that way, and the presumption strong. 
In some reptiles the place of the pineal must be looked for 
immediately under the pericranium, at the so-called parietal 
foramen. An approach to such a course of the cesophagus is 
figured in the embryo lamprey, after W. B. Scott; and there 
is the close connexion of the pituitary with the gastro- 
branchial or gastro-pulmonary inlet (and he avails himself of 
Mx. Balfour’s labours on this embryological point) in Elasmo- 
branch fishes. Indeed such a connexion almost remains in 
some birds, as in the cuckoo or goose, in the last of which the 
pituitary descends backwards half an inch in the sphenoid, 
and the canal communicates by two small openings with the 
lower surface of the skull. 
So far, then, the argument is, that the neural mouth in the 
invertebrate is a temporary one or embryonic in the vertebrate, 
and that the mouth and the cesophagus of the invertebrate 
become the conario-pituitary tract of the vertebrate. ‘This 
theory seemingly makes plain the unity of organization 
and composition between the two great divisions of animals, 
and also seems to bridge over a hiatus which has always been 
perplexing to the naturalist. 
The Professor, however, extends his conclusions further. 
We may see from his theory of the typical vertebra, from 
other views in the ‘ Comparative Anatomy of Vertebrates,’ 
as well as from the present paper, that he by no means lags 
behind in many of the philosophical theories first proposed by 
Goethe and Oken, and especially advocated in France pre- 
vious to 1830* by Geoffroy St.-Hilaire, Blainville, &c., but 
opposed strongly by Cuvier. Geoffroy took up certain views 
of two young anatomists, that there 1s perfect unity of plan 
between the highest mollusk (Sepia) and the vertebrate (a 
bird). All that is required to make the matter plain is, ac- 
cording to this, to bend the spinal column of the latter back 
upon itself, after the fashion of an acrobat, when a position is 
obtained apparently similar to the form of the sepia. Cuvier 
combats all this ; and his paper was published in the ‘ Annales 
* The writer attended Blainville’s/ecgons in the year 1880 at the Jardin, 
and with an introduction also to Cuvier himself. Most would admit 
that the transcendental views alluded to ran somewhat wild at this time, 
though many of them have been adopted since. 
Ann. & Mag. N. Hist. Ser. 5. Vol. x. 19 
