644 



NATURAL HISTORY OF AQUATIC ANIMALS. 



toward the posterior end, the spermatic organs (partes recurrentes), which, however, as is the case 

 with the ovaries, are sometimes wanting. 



The spermatic organs can be distinguished at the first 

 glance from the ovaries of the adult Eels and those of the 

 young Eels, not only by their lobular form, but also by their 

 shining, glassy appearance, by the surface of the individual 

 lobes, which is smooth and without leaflets, and by the much 

 greater density of the tissue, so that with a pair of pincers one 

 can take off a large portion of the organ, which could not 

 possibly be done with a more developed ovary whose tissue 

 is as tender as a cobweb, and is composed of small vessels 

 formed of a thin membrane and filled with eggs and fat. 



The fibrous tissue of the spermatic organs is composed 

 of vascular compartments with thicker partitions, inclosing, 

 according to the development of the organ, granular 

 globules (Fig. 7). 



These compartments are joined toward the inside and 

 the base of the lobes, which are united to a tube (vas deferens), 

 which, Cffical at the commencement, runs along the entire 

 length of the abdominal cavity, and opens near the straight 

 intestine (rectum) in a triangular pouch, which likewise con- 

 tains a vas deferens starting from the caudal part of the 

 spermatic organ. This pouch has its outlet in the general 

 orifice, which opens in the urethra (Fig. 8). 



As regards the development of the spermatic organs, I 



FIG. 6. Three lobes of the right testicle, with the defei 



a. Lobes, seen from their outer surface. 



b. Lobe, secMi i'runi HH inner surface. 

 r. Deferent canal. 



d. Anterior part of the same. 



en times). 



FIG. 5. Male Eel (natural size). 



a. Rinht testicle. 



b. I. I'll. teNtiele. 



< Right accessory parfc. 



d. Left accessory part. 



i\ Dividing memhrane. 



/. Deferent canal. 



0. Semiir.il pourh. 



/*. Anal clrprvssinn. 



i riin:irv liliiililer, covered to a great extent 



liv tin- seminal pouch. 

 k. l'';it mi tin- i iijit, side. 

 A . Similar fat covering the. stomach. 

 (. Fat, on the left side. 

 nt. Slim aeli. 

 ?l. Pylorus, 

 o. Liver, turned up to show the inner surface 



Ht',mr,'c"tf <" thu " H uphaj;u8 and the p} e j s measuring about 400 millimetersin length, the testicles 



;.. Cull l.la.liler. 

 , (/. I'ecioral tins. 



have observed that the lobes of these organs in young Eels, 

 measuring not more than 200 to 300 millimeters in length, 

 are not yet very distinct, forming two thin ribbons differing 

 but little from ovaries of the female in their average size. In 



can easily be distinguished from the ovaries. The former, 

 much straighten, and with tissue, as has been already remarked, much more solid, are provided 

 with a iiiiic.li more developed net-work of vessels; their lobes are very distinct and the deferent 

 canals are usually open, while the ovaries present the appearance of two continuous ribbons, 

 have ;i more delicate tissue, and an almost mucous appearance, and contain the eggs with the 

 germinative vesicles. 



