DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 181 



which gradually increases in height, and curving downwards towards its fellow fornos the 

 commencement of the inferior spinal canal, whose orifice is complete beneath the pos- 

 terior part of the twenty-fourth vertebra. The succeeding vertebraj are compressed, and 

 their inferior processes are in contact with each other, their truncated tips forming an 

 even, continuous line. Some way behind the second dorsal the spine inclines slightly 

 upwards, and the inferior processes have greater depth for a space, thus producing 

 a curved outline in connection with the attachment of the under lobe of the caudal. 

 The spinous processes form an obscure ridge on the fore part of the spine, but become 

 conspicuous about the sixteenth vertebra. They are very broad and irregular at the 

 fore part of the dorsal fins, become much shorter behind the second dorsal, lengthen 

 at the commencement of the upper caudal lobe, and taper away again towards the point 

 of the tail. Each dorsal is supported by ten rows of little compressed articulated bones. 

 In Torpedo narke the inferior spinal canal is completed at the thirty-fifth vertebra, and 

 the total number of vertebrae in the spinal column is ninety-four or ninety-five, the tail 

 being much shorter than in Narcine tasmaniensis. The ventral fins of this fish are 

 supported by twenty-one cartilaginous rays : in Torpedo narke the ventral rays appear 

 to be fewer, and the processes of the pelvic bones are shorter. 



The nervous system is in general similar to that of T. narke. The olfactory and 

 optic nerves are conspicuous from their size. The third and fourth pairs are not so 

 readily found. The fifth and electrical nerves are large, and are all composed of bundles 

 of fibres loosely bound together by cellular substance. The fifth issues from the skull 

 considerably behind the optic foramen. It sends some twigs to the muscles of the eye, 

 but its main trunks are distributed to the snout, upon which their twigs form a fine 

 lace-work. Two of these trunks, each as large as the optic nerve, pass over the eye, 

 and one which is still larger passing beneath it runs near the joint of the naso-pectoral 

 cartilage. The electrical nerves may be divided by the way in which they issue from 

 the skull into two or three sets. 1st. Two trunks issue in contact with each other im- 

 mediately before the quadrate bone, the anterior and smaller of which running forwards 

 over the joint of the naso-pectoral cartilage, passes near the last-mentioned trunk of the 

 fifth nerve, and then keeping along the upper edge of the semilunar arch of the pectoral 

 cartilages on the outside of the electrical apparatus, supplies the upper surface of the 

 pectoral fin. The second trunk goes directly to the fore part of the electrical apparatus. 

 2nd. Three large trunks issue from beneath the auditory protuberance behind the 

 quadrate bone, and pass between the several pairs of gills to the electrical apparatus. 

 3rd. A nerve coming from the skull almost in contact with the posterior trunk of the 

 second bundle sends twigs to the posterior gills, and then passing backwards beneath 

 the transverse process of the first vertebra, and through the pectoral girdle, traverses a 

 canal in that girdle, and is distributed to the upper surface of the pectoral fin, comple- 

 ting, in conjunction with the anterior trunk of the first bundle of electrical nerves, a 

 nervous circuit round the outer margin of the electrical apparatus. In Torpedo narke 



VOL. III. — -PART II. 2 B 



