440 TEMP. -MAJOR H. M. EVANS ON THE STINa-RAY. 



September there were in the great tank of the Aquarium of the 

 Zoological Station of Naples four Trygoii violacea and three 

 TJudassochelys caretta. One of the Tiygons died, and on examin- 

 ing it he found that the sting was broken and entirely gone. 

 After a few days one of the Tlmlassochelys would not eat any 

 more, unlike the others who ate with great appetite, and re- 

 mained in a corner of the tank : it lived thus for four days and 

 died on the fifth. On examining it he found the sting of the 

 Trygon buried quite 6 cm. under its right fin, piercing only the 

 skin and muscles ; in the part where the sting was buried the 

 tissue was of a violet colour. The wound was about 3 to 4 cm. 

 in length and breadth, and contained a putrid liquid with a most 

 ofiensive smell. 



The results of this investigation show : — 



i. The origin of the gland from a special layer of epithelium 



starting at the root of the spine, 

 ii. That the secreting tissue consists of regular follicles with 



ducts and central and lateral canals. 

 iii. That the secretion is discharged by means of nipples or 



filaments projecting from the canals. 

 iv. That there is a layer of muscular tissue surrounding the 

 centi'al canal. 



Works consulted. 



1. Bottard's " Les Poissons venimeux," 1889. 



2. Robert's " Giftfische und Fischgifte," 1902. 



3. Porta's paper in the " Anatomischer Anzeiger," xxvi. 



1905. 



4. Oalmette's "Les Venins," 1907. 



5. Cambi'idge Natural History, Fishes, 1904. 



There are full bibliographies in Bottard's work and in Porta's 

 paper. 



