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 (ylandula pterygopodii) of male Elasmobranchs 1 . 

 But from the similarity in many points between the general arrange- 

 ment of the poison-organs in Trachinus with those of Thalasso- 

 phryne 2 and Synanceia z , as described by Dr. GKinther, 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 be exceedingly interesting to ascertain the nature of the 

 poison of TracJiinus 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 remains 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 anguilla,ris (Zeitschrift f. wiss. 

 Zoologie, Bd. xlv., 1887, p. 532}. Coinp. also E. von Lendenfeld, on the lumi- 

 nous organs of Fishes, ' Challenger ' Beports, vol. xxii. Appendix B. Saville Kent 

 (15) states that Uranoscopus and its allies are provided with poison -glands, but 

 does not give his authority for this statement. 



2 Trans. Zool. Soc. vi. p. 437. 3 Pische d. Siidsee, i. p. 84. 



