194 JOURNAL OF COMPARATIVE NEUROLOGY. 
posterior palatine with reference to the pseudobranch does not 
therefore necessarily militate against the belief expressed in my 
earlier papers that this nerve is homologous with one of the 
pre-trematic branches of a typical branchiomeric nerve. But 
it can hardly be regarded as the true pre-trematic ramus in the 
strict sense, i. e., the nerve for the mandibular demibranch (cf. 
GREEN, 1900), as I have regarded it in the case of both Menidia 
and Gadus, for here it has nothing to do with the pseudobranch 
or any other structure which might be associated with a rudi- 
mentary gill. It bears a closer resemblance to the nerve in 
selachians which Mr. GREEN and I have compared with the 
chorda tympani. Indeed this resemblance is strikingly close, 
though it may be impossible to decide whether it is an actual 
survival of that condition or whether we have here a nerve 
primitively connected with a spiracular demibranch which upon 
being emancipated from its gill secondarily extended into the 
hyoid arch. 
The provisional identification of this nerve in Menidia as 
the r. pre-trematicus facialis was based primarily on its rela- 
tion to the pseudobranch, and the morphology of the 
teleostean pseudobranch is at present in a most unsatisfactory 
state, as I pointed out in a brief survey of the literature in the 
Menidia paper (’99, pp. 329-332). This organ was tentatively 
regarded as a vestigeal mandibular demibranch largely on the 
basis of Mauker’s (88) embryological studies of the arterial 
arches of the salmon. The matter cannot, however, be re- 
garded as definitely decided, for it appears from some researches 
by Mr. F. J. Cote now in process of publication that in Pleu- 
ronectes the vascular data indicate that the pseudobranch is 
hyoidean. I am permitted to quote from private correspondence 
from Mr. Cover, as follows: ‘‘As to the pseudobranch, in the 
plaice the nerve corresponding to JAcoBsoNn’s anastomosis of 
the cod is a very large nerve, whilst the so-called pre-trematic 
VII is small. Both join and go to the pseudobranch.” ‘‘Your 
pre-trematic VII = communis IX + communis VII [in the cod 
and plaice, but not in Menidia and Ameiurus, since these latter 
forms lack the Jacosson’s anastomosis—c. J. H.]. Therefore 
