PES DEVELOPMENT OF THE PARAPHYSIS: AND THE 
PINEAL REGION IN NECTURUS MACULATUS. ~~ 
BY 
JOHN WARREN. 
Demonstrator of Anatomy, the Anatomical Laboratory, Harvard Medical 
School. 
WITH 23 TEXT FIGURES. 
The presence of the paraphysis in Necturus was noted by Prof. C. S. 
Minot in his article “ On the Morphology of the Pineal Region, based on 
its Development in Acanthias ” (28), and a brief description of certain 
stages given. C. L. Herrick (15, Pl. VIII, Fig. 1, 3, 4) gives a brief 
account of the adult paraphysis, and shows it in the above figures, where 
it is named “ Preparaphysis.” Osborn (31, Pl. IV) shows the para- 
physis in an adult brain in comparison with the brains of other am- 
phibia. Kingsbury (21) describes briefly the adult paraphysis as well 
as a few of the earlier stages, and also gives an account of the epiphysis 
and the plexuses. I have found, however, no detailed account of all the 
- stages in the development of the paraphysis and the pineal region. This 
term is used here in the same sense as in Minot’s article, quoted above. 
The greater part of the specimens studied for this article were taken 
from the Embryological Collection of the Harvard Medical School, and 
the numbers of each section used are given. Other specimens were pre- 
pared specially for this purpose. In some cases where the plane of sec- 
tion was uneven, two or more sections were used in drawing the figures 
in order to show all the structures, which should appear in the median 
line. 
Fig. 1 is a median sagittal section through the brain of an embryo of 
8-9 mm. I am indebted to a colleague for the drawing of this section, 
as this stage is wanting in the collection. In the roof of the fore brain 
three arches are seen. From before backward these are the paraphysal 
arch, P. A., the post-velar arch, P. V. A., and the epiphysal arch, Hp. A. 
The first two are separated by the velum transversum, V, which marks 
the limit between the two subdivisions.of the fore brain. Hence the 
paraphysal arch belongs to the telencephalon, the other two to the 
AMUERICAN JOURNAL OF ANATOMY.—VOL. Y. 
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