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Show 1888.] POISON-ORGANS OF TRACHINUS. 361 opercular spine as " an offensive weapon," while Saville Kent (15) makes similar statements to those of Giinther and Day. Turning now to observers in other countries, I find that Cuvier (6, 7, & 8) and Bleeker (2; quoted by Dr. Giinther, 13) not only deny the existence of a gland, but even state that it is a mistake to suppose that the Weevers are poisonous at all. Cuvier, moreover, mentions the dorsal spines only. And as recently as 1886, Tybring (19) has made the following statement:-" In the Norwegian waters there are no poisonous fishes, but it is well known that the sting-bull [a local name for the Greater Weever, see Day, 9], may be dangerous if one happens to run the pointed dorsal fin into the finger, or any other part of the body." Canestrini (4) gives a brief reference to Byerley's paper, and acknowledges his conclusions. In Wiedersheim's ' Lehrbuch d. vergl. Anatomie '(20) the following passage occurs in the chapter on the integument (p. 20) : - " Weiter gehbrt dahin die unter der Stacheln der Riickenflosse von Trachinus liegende Giftdrvise. Sie ruht jederseits auf dem Grund vom sack-artigen Haut-Einstiilpungen, wahrend ihre Ausfiihrunsgange im Bereich der Stacheln liegen." (See also 21.) I am unable to state on whose authority this statement is made, as Professor Wiedersheim can-not at present lay his hands on the paper from which the passage was abstracted. But it will be noticed that no mention is made of the opercular poison-organ ; and that the description of the glands of the dorsal spines differs considerably from m y own observations. Before sending in the present paper for publication, a reference was given me by Professor Hubrecht to a work by Gressiu (14), and I much regret that I have been unable to obtain a copy, especially as from its title it is probably an important contribution to the subject. But as apparently this work is not known to most English ichthyologists, I have been advised to publish m y own observations independently. STRUCTURE OF THE POISON-APPARATUS. Opercular Organs.-The form of the opercular spine and its relation to the bony operculum are shown in the accompanying drawing (fig. 1, p. 362). A deep groove (gr) runs along both upper and under surfaces right to the apex ; and where the base of the spine joins the operculum the grooves are continued forwards for a short distance into small conical cavities (z), entirely surrounded by bone. Fig. 2 represents the third dorsal spine, which is slightly stouter than the others; the grooves here also extend from base to apex. Both figs. 1 and 2 are taken from T. draco \ the other figures (Plate XVII.) refer to T. vipera. I find there is no important difference between the two species as regards the structure of the apparatus, and have chosen the smaller species for histological examination, as it requires less decalcification and is more convenient for preparation. 1 I am indebted to Mr. J. J. Neale of Cardiff for a fresh specimen of this fish. |
