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Show 364 PROF. W. N. PARKER ON THE [June 19, with the epidermis a short distance below the apex can here also be made out. Fig. 8 represents a transverse section through the first and second dorsal spines. The first being shorter than the second, it is cut through at a relatively different level. So far as I am aware, there is only a single other case in which the presence of an integumentary gland which gives rise to a definite secretion has been distinctly proved amongst fishes : I refer to the gland of the clasper (glandula pterygopodii) of male Elasmohranchs1. But from the similarity in many points between the general arrangement of the poison-organs in Trachinus with those of Thalasso-phryne" and Synanceia3, as described by Dr. Giinther, I cannot help thinking that a careful histological examination of the " poison-bags " of these fishes might prove the existence of gland-cells in them also. A number of other fishes, which are said to be poisonous, might likewise repay further examination. It would he exceedingly interesting to ascertain the nature of the poison of Trachinus and to obtain more facts as to its effects. An account of an experiment which Prof. Allman made upon himself is given in the paper already quoted (1). He stung himself in the thumb with the opercular spine of a T. vipera, and found that it caused most excruciating pain which lasted about an hour and a half, as well as swelling and inflammation of the thumb and hand. The swelling lasted for some days, but the pain on pressure continued for more than a week. Sir William Jardine (10) quotes a Dr. Parnell as saying that the sting gives rise to a " painful wound, which causes the parts to swell and almost immediately to assume a dark-brown appearance which remaius for 4 to 6 hours." Couch (5) mentions that " there are instances where, within a few minutes, the pain has extended from the hand as high as the shoulder;" and states that the danger is not wholly removed after the fish is dead: on this account it is provided by law in some places that the spines shall be removed before the fish is offered for sale in the market. Allman, however, found that inoculation from a fish about 24 hours dead only caused a slight smarting. Byerley (3) describes the erection of the dorsal spines and operculum, and with regard to the effects of the poison gives the following details :-The acute pain caused by the punctures is stated to last usually four or five hours, and to leave the parts in a numb and tender state for some time afterwards. In some cases acute inflammation follows, causing sloughing or mortifying of the parts around the puncture, and even 1 See Petri, Zeitschrift f. wiss. Zoologie, Bd. xxx. Brock has described some gland-like cells in the curious dendritic appendage which is situated behind the urinogenital papilla of PLotosus anguillaris (Zeitschrift f. wiss. Zoologie, Bd. xiv., 1887, p. 532). Comp. also R. von Lendenfeld, on the luminous organs of Fishes,' Challenger' Reports, vol. xxii. Appendix B. Saville Kent (15) states that Uranoscopus and its allies are provided with poison-glands, but does not give hie authority for this statement. 2 Trans. Zool. Soc. vi. p. 437. 3 Fische d. Siidsee, i. p. 84. |