112 



happened in the dusk or semi-darkness when the Dogfish had 

 its eyes open is uncertain, but on this occasion it swallowed 

 the Blaasop whole, without any hesitation, and then returned 

 to a quiet corner, as Dogfish do after a heavy meal. After a 

 considerable time it seemed uneasy, and finally became very 

 sick, ejecting half-digested fragments of Blaasop from time 

 to time. No serious results followed, however, and next day 

 the Dogfish was quite normal. On one occasion a large Star- 

 fish (Asterias) got hold of a piece of Blaasop hver, and took it 

 quite readily, folding it in its arms, and enveloping it in the 

 fine membranes of its stomach. It held it thus from an after- 

 noon till the following morning, when most of the liver had 

 disappeared. The remainder was taken possession of by 

 another Starfish, and finally none was left. The Starfish 

 seemed none the worse for their meal. It cannot be concluded 

 from this single instance, however, that the Starfish actually 

 took the poison into their system, as much of the brown sub- 

 stance of the liver became somewhat flocculent and floated 

 away. The connective and some other tissues, however, were 

 apparently digested.* 



With regard to the peculiar habit of distending the body 

 (hence the name Blaasop), this may be defensive, as shown in 

 the case above mentioned. When drawn up on shore with 

 the seine net, the fish inflate themselves with air, especially if 

 irritated. No artificial irritation was found to produce the 

 inflation in the water and, only on one other occasion, was a 

 Blaasop observed to become distended in this way. It had 

 been several months in the tank, and once it was found to be 

 so distended that the body was about spherical. A few 

 minutes after this was observed, it suddenly assumed its 

 normal size. No air bubbles were seen escaping. The 

 accepted explanation of the inflation of these fishes is that 

 when alarmed it distends itself with air taken in at the surface 

 of the water. It then floats, belly upwards, and is thus pro- 

 tected from its enemies. This may be true of other species of 

 globe-fish, but in the case of the Blaasop the distension with 

 air seems to occur only when the fish is removed from the 

 water. 



A species closely alhed to the Cape lorm occurs in Durban 

 Harbour. It makes off rapidly when surprised and if chased 

 for a short distance in the shallow water, in which it usually 

 occurs, it buries itself in the sand, and when lifted up becomes 

 greatly distended. 



* For a detailed account of the poison found in the tissue (chiefly the genital 

 organs) of the Tetrodontidje, see " Uber die giftigen Bestandteile des Tetrodon," 

 Zeitsch. d. med. Ges. in Tokio 8, Heft 14. 



