The Blennies : Blenniidas 529 



of fresh examples. The sacs are without an external muscu- 

 lar layer and situated immediately below the loose thick skin 

 which envelops their spines to their extremity. The injection 

 of the poison into a living animal, therefore, can only be effected 

 by the pressure to which the sac is subjected the moment the 

 spine enters another body. Nobody will suppose that a com- 

 plicated apparatus like the one described can be intended for 

 conveying an innocuous substance, and therefore I have not 

 hesitated to designate it as poisonous; and, Captain Dow 

 informs me in a letter lately received, 'the natives of Panama 

 seemed quite familiar with the existence of the spines and of 

 the emission from them of a poison which, when introduced 

 into a wound, caused fever, an effect somewhat similar to that 

 produced by the sting of a scorpion ; but in no case was a wound 

 caused by one of them known to result seriously. The slightest 

 pressure of the finger at the base of the spine caused the poison 

 to jet a foot or more from the opening of the spine.' The great- 

 est importance must be attached to this fact, inasmuch as it 

 assists us in our inquiries into the nature of the functions of 

 the muciferous system, the idea of its being a secretory organ 

 having lately been superseded by the notion that it serves 

 merely as a stratum for the distribution of peripheric nerves. 

 Also the objection that the sting-rays and many Siluroid fishes 

 are not poisonous because they have no poison organ cannot 

 be maintained, although the organs conveying their poison 

 are neither so well adapted for this purpose nor in such a perfect 

 connection with the secretory mucous system as in Thalasso- 

 phryne. The poison organ serves merely as a weapon of defense. 

 All the Batrachoids with obtuse teeth on the palate and in the 

 lower jaw feed on Mollusca and Crustaceans." 



No fossil Batrachoididce are known. 



Suborder Xenopterygii. The clingfishes, forming the subor- 

 der Xenopterygii (Zeros, strange; nrepvZ, fin), are, perhaps, 

 allied to the toadfishes. The ventral fins are jugular, the rays 

 i, 4 or i, 5, and between them is developed an elaborate suck- 

 ing-disk, not derived from modified fins, but from folds of the 

 skin and underlying muscles. 



The structure of this disk in Gobiesox sanguineus is thus 

 described by Dr. Gunther: 



"34 



