566 EDWARD PHELPS ALLIS, JR. 
In an 80 mm. specimen of Lepidosteus osseus and a 141 mm. 
specimen of Polyodon spathula the vena jugularis has the same 
relations to the several cranial nerves that it has in Amia, and I 
find similar conditions in young specimens of Hiodon tergisus, 
Scorpaena scrofa and Cottus aspera, and in the adults of Scom- 
bresox saurus, Gadus merlangus and Trigla hirundo. In a 57 
mm. specimen of Catostoma occidentalis and a 40 mm. specimen 
of Gastrosteus aculeatus the glossopharyngeus section of the vein 
was the only one which lay dorsal to the related nerve. In an 
adult Cyprinus carpio and a 48 mm. specimen of Carassius 
auratus the facialis section of the nerve alone had this position. 
In embryos and the adult of Ameiurus nebulosus the vein lay 
ventral to all of the four nerves here under consideration, the 
entire vena cardinalis anterior thus here persisting as the defini- 
tive vein; Ameiurus, and hence probably all of the Siluridae, thus 
differing from other teleosts in this respect as well as in the 
arrangement of the pseudobranchial and carotid arteries, the 
innervation of the recti muscles of the eye-ball, and the condition 
of the myodome (Allis, ’08, 709). 
In Ceratodus embryos of Semon’s Stage 45, Greil (713, figs. 
2-3, pl. 51) shows the vena jugularis, called by him the capitis 
lateralis, lying ventral to the nervus trigeminus and dorsal to 
the nervi facialis, glossopharyngeus and vagus, but, as in the 
Plagiostomi and Teleostomi, ventral to the latero-sensory nerves 
which issue with the nervi trigeminus, glossopharyngeus and 
vagus. In Stage 48 of this fish (l.c. fig. 2, pl. 55)- the vein appar- 
ently still lies ventral to the nervus trigeminus and the same 
latero-sensory nerves, but it here lies ventral also to the nervus 
facialis, though still dorsal to the glossopharyngeus and vagus. 
This must, accordingly, be a less advanced stage than that shown 
in the embryo of Stage 45, unless it be that the vem change, a 
second time, its relation to the nervus facialis. But however 
this may be, it is evident that the definitive vein in this fish is 
of the plagiostoman and reptilian (Lacerta) type rather than the 
teleostean or amphibian. 
One further feature of this vein may here be mentioned. The 
large orbital venous sinus, found so well developed in the Plagi- 
