1894.] NATURAL SCIENCES OF PHILADELPHIA. 43 



being present in the cod, and in not transmitting the portio dura of 

 the seventh nerve, the latter also not existing in the cod-fish. ^* If the 

 bone No. 6 in the cod-fish be compared, however, with the great 

 wing of the sphenoid in Man (Figs. 1, 2, a) it will be observed that it 

 agrees with the latter (alisphenoid) in articulating vath. that part of 

 the basi- cranial axis corresponding to the basi-sphenoid, and with the 

 parietals in entering into the formation of the lateral wall of the 

 cranium, supporting the mesencephalon, and in being notched anter- 

 iorly (perforated iu the carp) for the transmission of the superior and 

 inferior maxillary branches of the fifth nerve. The bone No. 6 in 

 the cod differs from the alisphenoid in Man, as already mentioned, in 

 supporting part ot the membranous labyrinth and in the notch trans- 

 mitting the inferior maxillary branch of the fifth nerve being situated 

 in the anterior part of the bone rather than in the posterior part as 

 is the case in Man. 



In the consideration of the relative posterior of the notch v in the 

 bone No. 6 in the fish and that of the foramen ovale in the alis- 

 phenoid of Man, (Fig. 2, fo), the fact appears to have been entirely 

 lost sight of that the notch or foramen in the fish corresponds to two 

 distinct foramina in Man : the foramen rotundum, (Fig. 2, r) and 

 the foramen ovale, (Fig. 2, fo) transmitting respectively the super- 

 ior and inferior maxillary branches of the fifth nerve, and that the 

 part of the notch in the fish, (Fig. 6, V) corresponding to the foramen 

 rotundum in Man, is situated anteriorly just as is the case in Man. 

 The situation of the exit of the superior maxillary nerve is therefore 

 substantially the same in the bone No. 6 in the cod (and absolutely 

 so in the carp) as in the alisphenoid of Man. The objection that 

 might still be urged that that part of the notch corresponding to the 

 foramen ovale is situated anteriorly in the fish but posteriorly in 



^^ The author is familiar with the view entertained by some anatomists that 

 hyomaiulibular branches of the fifth nerve represent in the fish the branches of 

 the portio dura of the seventh nerve or facial in Man. Such an interpretation 

 is, however, untenable, being based upon the assumption that the quadrate bone 

 (jujral caisse hypotympanic) in the fish is thehomologue of the incus in Man, the 

 articulare corresponding then to the malleus. As the quadrate and malleus are, 

 however, developed as ossifications oi the proximal ends of Meckel's cartilage 

 (mandibular arch) the quadrate must be the homologue of the malleus, not the 

 incus, if it be homologous with either of the ear bones. The hyomandiliular bone 

 (temporal mastoidien epitympanic) in the fish is homologous with the incus, 

 these bones Ix'ing developed through the ossification of the proximal ends of the 

 hyoid arch. It must be admitted, however, that this last view leaves still un- 

 cxplaini'd why the articulare in the mandibular arch of the fish and the same 

 bone together with the others entering into the formation of the lower jaw of the 

 alligator are not represented in Man. 



