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sections have also been made use of, to, in a way, control the work 

 on sections. These sections were in part prepared by Mr. Allen at 

 Pacific Grove, and in part by Mr. G. E. Nicholls, my assistant here. 

 Various methods of staining have been tried, but in no single one of 

 the many series so far prepared has it been possible to always 

 distinguish nerve fibres from the membranous and fibrous tissues that 

 partly or wholly envelope, and frequently penetrate the muscles. As the 

 branches of certain of the nerves, and even the main nerve trunks 

 themselves, frequently perforate the muscles, and as these nerves 

 frequently lie close against, or may perhaps be partly enveloped in 

 the fibrous tissues, it has been impossible to always tell whether 

 certain of the lines of tissues that penetrate and end in certain of 

 the muscles were fibrous or nervous. I can not therefore positively 

 affirm, that certain muscles, said by Müller to be innervated by 

 branches of the ophthalmicus, do not receive certain branches of that 

 nerve, but I am positively convinced that if any such branches are 

 sent to the muscles they do not innervate them. 



Cranial Nerves. 

 The so-called trigeminal nerves of Bdellostoma arise, in the adult, 

 from a ganglionic complex that lies against what has heretofore been 

 always considered as the outer, lateral wall of the membranous 

 cranium, there lying dorsal to the anterior end of the trabecular bar, 

 and dorsal to, or partly in, fenestra (1). The ganglionic mass is, however, 

 enclosed in a fibrous membrane that arises, dorsally, from the side 

 wall of the membranous cranium, runs laterally, downward, and then 

 inward around the ganglion, and has its ventral attachment to the 

 side wall of the cranium below the ganglion. This membrane is thus 

 an offshoot of the membranous cranium. Anteriorly it is delicate, 

 and there lies slightly dorsal to the trabecula ; posteriorly it is strong, 

 and here, as it passes inward toward the cranium, it is closely 

 attached to the dorsal surface of the trabecula. In this posterior 

 region a second fibrous membrane arises from the dorso-mesial edge 

 of the anterior arm of the pterygo-quadrate, runs upward close against 

 the lateral surface of the first membrane, and then upward internal 

 to the trunk muscles. This second membrane is continued ventrally 

 across the dorso-lateral surface of the pterygo-quadrate, and then 

 from the ventro-lateral edge of that cartilage downward and mesially 

 around the lateral and ventral surfaces of the velar muscles, toward, 

 but apparently not definitely to, the lateral edge of the hypophysial 

 plate. 



