371 
It would however not be at all in accord with both ZrmeLER’s (1908) 
and Broumer’s (1909) conclusion that there is but a single pre- 
mandibibular segment in embryos of Chlamydoselachus. 
Reis (1896), it is to be noted, agrees with JAEKEL that there 
is a premandibular element in the upper jaw of Acanthodes Bronni, 
and he calls it the Praepalatoquadratum and considers it to be the 
homologue of the selachian orbital (palato-basal) process. And it 
is further to be noted that Hasen (1900) considers both the otic 
capsules and the alae temporales (vorderen Keilbeinanlagen) of human 
embryos to represent parts of adjacent vertebrae that have become 
incorporated in the preoceipital part of the skull. 
Palais de Carnolés, Menton, Nov. 30, 1913. 
Literature. 
Auuis, E. P. jr., a) The Cranial Muscles, and Cranial and first Spinal Nerves 
_ in Amia calva. Journ. of Morphology. Boston 1897, Vol. 12. 
— b) Morphology of the Petrosal bone and of the Sphenoidal region of the Skull 
of Amia calva. Zool. Bulletin. Boston 1897, Vol. 1. 
— The Morphology of Certain of the Bones of the Cheek and Snout of Amia 
calva. Journ. Morphology. Boston 1898, Vol. 14. 
— The Premaxillary and Maxillary Bones and the Maxillary and Mandibular 
Breathing Valves of Polypterus bichir. Anat. Anz., 1900, Vol. 18. 
— The Lateral Sensory Canals, the Eye-muscles, and the peripheral distribution 
of certain of the Cranial Nerves of Mustelus laevis. Quart. Journ. Microsc. 
Sci. London 1901, Vol. 45. 
— The Skull, and the Cranial and first Spinal Muscles and Nerves in Scomber 
scomber. Journ. Morphology. Lanc. 1903, Vol. 18. 
— The Pseudobranchial and Carotid arteries in Ameiurus. Anat. Anz. Jena 
1908, No. 10. 
— The Cranial antomy of the Mail-cheeked Fishes. Zoologica, 1909, Bd. 22, H. 57. 
— The Homologies of the Ethmoidal region of the Selachian Skull. Anat. Anz. 
Jena 1913, Bd. 44, No. 14. 
Broumer, P., Der Kopf eines Embryos von Chlamydoselachus und die Seg- 
mentierung des Selachierkopfes. Jen. Zeitschr. f. Naturwissenschaft 1909, 
Bd. 44, Heft 2/4. 
DAHLGREN, U., Maxillary and mandibular breathing valves in Teleosts. Zool. 
Bulletin. Boston 1898, Vol. 2. 
Fucus, H., Uber das Pterygoid, Palatinum und Parasphenoid der Quadrupeden, 
insbesondere der Reptilien und Säugetiere, nebst einigen Betrachtungen über 
die Beziehungen zwischen Nerven und Skeletteilen. Anat. Anz. Jena 1910, 
Bd. 36, Nr. 2/4. 
— Über einige Ergebnisse meiner Untersuchungen über die Entwicklung des 
Kopfskelettes von Chelone imbricata (Material VoELTZKow). Anat. Anz., 
Ergänzungsheft zum 41. Bd. Jena 1912. 
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