59] THE SKULL OF AM lURUS— KINDRED 59 



synonomy may be found, in common with that of the other cranial bones, in 

 tables given by Owen (1848), VroHk (1873), and Starks (1901). VroHk very 

 briefly describes this bone as a 'perichondrostische' ossification, that is, what 

 is here called a dermal ossification. It is figured for the carp, Silurus and other 

 teleosts, but he does not discuss it further. 



In the Cyprinoids (Sagemehl, 1891) it encloses the olfactory nerve and the 

 ophthalmic branch of the trigeminus, has an articular facet for the palatine, 

 and is called the prefrontal. It projects very abruptly from the lateral surface 

 of the cranium, separating the nasal fossa and the orbit. Its developmental 

 relations are not discussed. These same relations also hold true for the Char- 

 acinidae as described by the same author (1885). 



Gegenbaur (1878) calls this bone the 'ethmoide laterale' or 'praefrontale' 

 in Alepocephalus. He distinguishes two parts, a lateral and a medial, the 

 latter is developed from the ethmoid cartilage and forms the inner wall of the 

 olfactory canal. He claims that the sculpturing on the dorsal surface is 

 arranged concentrically and that the ridges represent lines of growth. The bone 

 does not have the extensive articulation that it has in Amiurus, but is hmited 

 to the cap of the ectethmoid process. 



McMurrich (1884b) made two statements concerning this bone in Amiurus, 

 which contradict each other. In one place (p. 277) he says that the upper 

 surface of the bone is very irregular and has numerous foramina connected 

 with the mucous canal system. Farther along in the same paper (p. 280), 

 he says that there is no connexion between the ectethmoid and the mucous 

 canal lying dorsal to it. If the first statement were qualified to mean nerve 

 foramina, as I think he really means, there would be no confusion in interpret- 

 ing his statement. Since there are canal foramina in some of the bones of this 

 region, this qualifying statement should be made. 



Gaupp (1906), in remarking upon the development of this bone in Salmo, 

 calls it the 'pleurethmoidale, ' introducing an entirely unnecessary term. If 

 one standard of nomenclature is to be adopted in comparative osteology, it 

 should be adhered to as far as possible. Anyone reading Gaupp's papers is 

 at once struck by the flood of new and unnecessary terms throughout all of 

 them. According to this investigator, the ectethmoid of the adult Salmo is a 

 true perichondrial ossification formed around the planum antorbitale (ecteth- 

 moid process). The adult condition is the result of endochondrification and 

 resorption, with an added ossification formed by the ligament connecting it 

 to the palatine. The bone includes the ophthalmic branch of the trigeminus, 

 and the anterior ossicle of the infraorbital chain of bones is attached to its 

 lateral surface. 



ALUs' (1910) description of the development of this bone in the mail- 

 cheeked fishes (Loricati) is given earlier in the paper, but we can compare the 

 adult bones at this time. As was stated previously, both have perichondrial 

 and dermal elements, although AUis claims that the latter is perichondrlia 



