. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. i6o ANNALS OF THE SOUTH AFRICAN MUSEUM crystalline co crystalline cone sta reti nu Ian eel I s zone of rhabdomes neurosecretory cells medulla terminalis to connective tissue X-organ (SPX & MTG to dorsal retracto adductor muscle med laI retractor ecu I omotor oculomotor ner. gangi i onaris medulla externa medu 1 la i nterna sinus gland to connective tissue sinus gland fibre tract ) abductor muscle i nus gland nerve ateral retractor muscle to ventral retractor muscle oculomotor nerve la r nerve I F
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. i6o ANNALS OF THE SOUTH AFRICAN MUSEUM crystalline co crystalline cone sta reti nu Ian eel I s zone of rhabdomes neurosecretory cells medulla terminalis to connective tissue X-organ (SPX & MTG to dorsal retracto adductor muscle med laI retractor ecu I omotor oculomotor ner. gangi i onaris medulla externa medu 1 la i nterna sinus gland to connective tissue sinus gland fibre tract ) abductor muscle i nus gland nerve ateral retractor muscle to ventral retractor muscle oculomotor nerve la r nerve I Fig. 59. Diagrammatic impression of ner\^es of right eye of adult, based on serial sections and dissections. The approximate positions of the sinus gland and neurosecretory cells are indicated. (fig. 59). The sub-branches of these are distributed to the eye muscles in the optic cup and are often linked by delicate collateral plexuses. Oculomotor I a supplies the lateral retractor and the abductor eye muscles and extends distally to the subretinal connective tissue in the dorso-lateral region of the optic cup. It has a further relatively strong medial branch, which dips ventrally to inner- vate the ventral retractor eye muscle and gives rise to a long offshoot that travels below the distal part of the optic nerve and proceeds to the ventro-medial subretinal connective tissue. The second branch, oculomotor I b, is equally widespread and, after inner- vating the medial retractor, the dorsal retractor, and the adductor eye muscles, it continues distally to the dorso-medial subretinal connective tissue. One of its most interesting subdivisions is the sinus gland nerve (fig. 59), which passes forward and penetrates the neurilemma at the base of the medulla terminalis. In sections of the eye it is possible to trace its deeply stained basophilic fibres. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
