of the Fishery Board for Scotland. 



199 



which point a width of '75 mm. was found. It was noticed that the 

 length of the lobe varied from 15 to 4 mm. Behind the anus, the lobes 

 became still narrower, and at its posterior extremity the testis was 

 reduced to a filamentous termination. The caudal portions and partes 

 recurrentes of both testis were lobed, but the separation between the lobes 

 was not so distinctly marked as in the abdominal portions. The lobes 

 were irregular in length, and in greatest breadth did not exceed "75 mm. 

 The pars recurrens on the right side ended in a filamentous prolongation 

 at a point 4 mm. behind the anus. 



The left testis began 24'5 mm. behind the diaphragm, and 28'5 mm. 

 from the insertion of the pectoral fin. The abdominal portion was 7 cm. 

 long and consisted of 25 lobes. The testis ended in a filamentous tip at a 

 distance of 27 mm. behind the anus. The pars recurrens was 14 mm. 

 long. 



The breadth of the lobes at the anterior part of the left testis was 

 1 mm. At a distance of 4 cm. from the anterior end the width began to 

 diminish, and at the anus it was reduced to -7 mm. The length of the 

 lobes varied from 1 '25-4*5 mm. Behind the anus the width of the lobes 

 was still further diminished, the caudal portion and pars recurrens ending 

 in filamentous tips. The separation of the lobes of the latter was not 

 deeply marked. 



The testicular lobes are smooth, without leaflets, and have a shining 

 glassy appearance. They are of much firmer consistence than the ovary, 

 and show no trace of ovules nor of adipose cells. The greatest breadth of 

 the lobe is given by Syrski as 3 mm.; Robin described a testis, of which 

 the lobes were 2 mm. in breadth, usually a little longer than wide, 

 measuring in greatest thickness 1 mm. out of the time of reproduction. 

 The lobes of the testis examined by Cattie * were 0*5 mm. in depth of 0*75 

 mm. in length. Histological examinations of the testis have been made 

 by several zoologists, at evidently different stages of development. The 

 fibrous tissue of the lobe is composed of vascular compartments with 

 thicker partitions, inclosing, according to the development of the organ, 

 granular globules (Syrski). Kingsley f found that the male organs of the 

 American eel (Anguilla bostoniensis) agreed almost exactly with the 

 description given by Syrski. Cattie gives the following description : — 

 ' The histological structure of the lobe organ was investigated by Freud. 

 1 He found an areolar structure with connective tissue corpuscles, similar to 

 ' the histological structure of the immature testis of fishes. My prepara- 

 ' tions had a similar appearance as long as the smaller examples were the 

 ' subjects of investigation. In the largest specimens of eels with lobulated 

 4 organs investigated by me (445 mm. [17 J inches] long), I found cylin- 

 ' driform strings, which passed from the bases to the tips of the lobes, and 

 1 were filled with cells. After repeated trials with the most different 

 * reagents, I did not succeed in clearly distinguishing a nucleus in these 

 1 cells. According to Jacoby (Der Fischfang in der Lagune von Coraa- 

 ' cchio), Von Siebold saw similar strings of cells in an eel in which the lobes 

 1 were very strongly developed. These strings of cells presented to the eye 

 ' themost undoubted similarity to the testicular mother-cells of spermatozoa.' 

 Ryder also was of the opinion that the microscopic examination of the 

 lobe demonstrated its testicular nature. * $ Syrski states that these lobu- 



* Cattie, ' Ueber die Genitalien der mannlichen Aale, &c.,' Phil. Nat. Cand. 

 Docent. an der Eealschule Zu Arnheim (Holland). Trans, in Proc. U.S. Nat. Mus. t 

 vol. iii., 1880, p. 280. 



t Packard and Kingsley, 'The Discovery of Male Eels,' in American Naturalist, 

 vol. xiii., 1879. 



+ Ryder, 'Note on the Male Organs of the Eel,' in Bulletin U.S. Fish. Comm., 

 vol. v., 1885. 



