i 
‘ 
z 
* 
395 
upper or cranial extremity, however, some strong fasciculi 
take a semicircular course around its anterior and lateral sur- 
faces, and are attached to the bones on either side ; and around 
the lower end also are some oblique and partly annular fibres, 
which are attached to the central appendix and to the border 
on either side. 
* I shall next allude to the nerves which are distributed to 
the proboscis, and which extend its entire length: they are 
four in number, that is, two on each side, and, like the muscles, 
are symmetrically arranged ; these nerves are the facial, or 
the portio dura of the seventh and the infra-orbital or supra- 
maxillary division of the fifth cerebral nerves. These nerves 
are remarkable for their size and length, and for the numerous 
plexuses they form with one another. The portio dura, or the 
seventh, is about the size of the little finger, and between the 
point of its exit from the stylo-mastoid foramen in the base of 
the skull, and its entrance into the proboscis, pursues a curved 
course about two feet in length; in this course it sends many 
branches to the glands and muscles on the side of the face, and 
then enters the upper and lateral part of the proboscis between 
the anterior and lateral longitudinal muscular fasciculi, and is 
joined in this situation by the superior maxillary nerve, the 
second division of the fifth pair ; this great nerve, fully the 
size of the middle finger, escapes from the infra-orbital fora- 
men, gives off a few branches to the lower eye-lid and to the 
integuments, and then descends into the same sulcus in the 
proboscis with the seventh. The two nerves now unite, butthey 
soon separate and divide, the divisions reuniting so as to forma 
most intricate nervous plexus; and, as you may observe in the 
dissection before you, these nerves pursue a similar arrange- 
ment during their long course down the trunk, until within a 
few inches of the extremity. This chain of plexuses resembles 
a thickly tangled skein of silk extending from one end to the 
other. When the dissection is carried deeper, the same plexi- 
form appearance is observed, the nerves running in the ten- 
dinous sheaths, already described, in courses one beneath the 
