542 JULIA B. PLATT. 
arch arise from the root of those of the first arch. These facts 
suggest that a vagus segment is interpolated in the original 
metamerism. 
(7) While some fibres from the lateral line ganglion enter the 
vagus root, most of the fibres enter the brain through the root 
of the glosso-pharyngeus, using for this purpose the neural 
crest cells which bridge the space between the vagus and 
glosso-pharyngeal ganglia. 
(8) Many cells of the neural crest of the trunk do not take 
part in the formation of spinal ganglia, but form part of the 
connective tissue at the side of the spinal cord. 
(9) The motor nerves of the trunk appear before the spinal 
ganglia, and are formed by the migration of bipolar cells from 
the spinal cord. 
(10) The nerve which underlies the infra-orbital sensory line 
divides throughout its length into two nerves connected 
respectively with the Gasserian and facial ganglia, thus 
repeating the relation of the nerves derived from the supra- 
orbital ridge, the ophthalmicus profundus, and superficialis. 
(11) The ramus hyomandibularis and its direct continuation, 
the mandibularis internus, appear in Necturus as the post- 
trematic branch of the hyoid arch, while the hyoid nerve 
resembles the lateral nerves of the posterior arches. 
(12) Cells of ectodermic origin contribute to the formation 
of blood-corpuscles in the branchial region. 
(13) Although delicate protoplasmic prolongations connect- 
ing cell with cell initiate the specialised co-ordination of the 
nervous system, a common reticulum, such as Sedgwick de- 
scribes, into which nuclei migrate, does not exist in Necturus. 
(14) The root of the sensory nerve is no index to the seg- 
mental value of the nerve. 
Battimorr; April 8th, 1895. 
