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Nachdruck verboten. 



On the poison-organs of Trachinus. 



Voii Prof. W. Newton Pabkfk in Cardiff. 



In each of the British Weavers, Trachinus draco and T. v i - 

 pera, the operculum is provided with a large grooved and pointed 

 spine, which extends backwards and projects freely posteriorly. The 

 five or six strong spines of the anterior dorsal fin are also grooved and 

 pointed. 



It is well known that wounds caused by these spines give rise 

 to considerable inflammation and pain, but it bas been supposed by 

 most Icthyologists that the poisonous effects are not due to the se- 

 cretion from any special gland, but are produced simply by the la- 

 ceration of the wound and the injection into it of some of the mucus 

 from the integument. 



This question has an additional interest, as there are so few 

 instance in which the existence of definite integumentary glands has 

 been proved in fishes. 



The only English observer who has mentioned the presence of 

 glands in Trachinus is Byerley (Proc. Lit. and Philosoph. Soc. 

 Liverpool, No. 5, 1849): but his statements were not sufficiently con- 

 clusive to settle the point, and they were afterwards doubted by Gün- 

 ther and others. Allman (Ann. of Nat. Hist., Vol. VI, 1841) had 

 previously stated that a „pulpy mass" within the grooves of the spines 

 might be of a glandular nature, but adds that this is simply a con- 

 jecture. 



The only other statement as to the existence of poison-glands in 

 these fishes which I have seen , is contained in Wiedersheim's Lehr- 

 buch d. vergl. Anät. (2. Aufl., 1886, p. 20), and runs as follows: 

 „Welter gehört dahin die unter den Stacheln der Rückenflosse von 

 Trachinus liegende Giftdrüse. Sie ruht jederseits auf dem 

 Grund von sackartigen Hauteinstülpungen, während ihre Ausführungs- 

 gänge im Bereiche der Stacheln liegen." But Professor Wiedersheim 

 is unable at present to find the reference to the paper from which this 



