Miscellaneous. 477 
On the Development of the Branchial Pouches and Aortie Arches in 
Marine Turtles, from Investigations upon Embryos of Chelonia 
viridis. By Dr. J. F. van Bewme.en, of Batavia. 
1. The earliest rudiments of the branchial pouches and aortie 
arches in turtles entirely agree with those found in lizards and 
snakes ; their subsequent development, however, pursues a different 
course, and is more in accordance with the conditions observed in 
birds than with those exhibited in the case of the other reptiles. 
2. As in the last-mentioned animals, the rudiments of five 
branchial pouches and six aortic arches are primitively formed. 
Besides these, on the posterior wall of the hindermost branchial 
pouches, where the branchial section of the gut narrows to form the 
pharyngeal portion, an additional pair of pouch-shaped evaginations 
are developed, just as the same process takes place in snakes. They 
lie to the right and left in the region in question, where in lizards 
there arises on one side only, namely on the left, an epithelial 
evagination, which becomes constricted off in the form of a vesicle 
previously termed by me the “ supra-pericardial body” (‘ Supra- 
pericardialkorperchen”), since I regard it as homologous with the 
derivatives of the branchial gut in the Selachians, upon which I 
bestowed the same designation. 
3. The three foremost branchial pouches are undoubtedly open 
during a short time. Whether this is also the case with regard to 
the two hindermost ones I cannot definitely say, but it appears to 
me to be probable with respect to the fourth branchial pouch. 
4, Asin the Amniota, the tuba Hustachii arises from the dorsal 
portion of the first branchial pouch ; its external aperture soon closes 
again, while the tympanic cavity does not develop until much later. 
5. The second branchial pouch lies close behind the first; the 
portion of the branchial gut separating the one from the other 
possesses a wider lumen than the section following further towards 
the rear. The dorsal apex of the second branchial pouch expands 
into a follicle-shaped epithelial bud; this, however, does not become 
constricted off, as in the case of the lizards, where it forms the first 
(foremost) lobe of the thymus. Neither does the second branchial 
cleft become entirely constricted off from the branchial gut, to 
remain as an epithelial vesicle lying in the midst of the connective 
tissue of the neck, as in the case of the snakes. In the subsequent 
development of the embryo the second branchial pouch simply 
becomes aborted, as in the birds. 
6. The cleft-shaped external apertures of the foremost branchial 
pouches undergo, as in the case of birds, a considerable backward 
movement. This shifting of position is occasioned by the backward 
outgrowth of the branchial arches, which consequently commence 
to cover one another in imbricated fashion. The second branchial 
cleft in particular undergoes so much backward displacement that 
the corresponding branchial pouch becomes greatly elongated in the 
