The Blennies: Blenniidz 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having lately been superseded by the notion that it serves 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 Batrachoidide are known. 
Suborder Xenopterygii—The clingfishes, forming the subor- 
der Xenopterygit (€evos, strange: marepvé, 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 Gobtesox sanguineus is thus 
described by Dr. Gtnther: 
—34 
