556 General Notes. [ M ay , 



delicate layer, formed by cellular tissues and smooth muscular 

 fibres ; on its internal surface there are projecting lamellae, which 

 increase the extent of the secreting surface; below this, is a layer 

 of prismatic cells, which are filled with protoplasm, containing in 

 suspension, and in abundance, fine rounded granulations, which are 

 characteristic of the poison of the scorpion, and hide the nuclei, 

 which only become apparent on the addition of acetic acid ; these 

 are the cells which elaborate the poison, and from which it escapes, 

 by the rupture of the cells, into the central cavity of the organ. 



Physiologically, this poison is very active, and that in direct re- 

 lation to the quantity introduced ; one drop is soon fatal to a 

 rabbit and still more active on a bird ; seven to eight frogs may be 

 killed by one drop, and the hundredth part of one is fatal to an 

 ant of large size. It would appear to affect the nervous system, 

 and has undoubtedly a marked action on striated muscle, sup- 

 pressing spontaneous and reflex movement. — jFournal of the Royal 

 Microscopical Society. 



The Habits of the Snake Bird. — The mechanism of the neck 

 in the darters (Plotus) is treated by W. A. Forbes in the Proceed- 

 ings of the London Zoological Society. The darters feed entirely, 

 so far as Mr. Forbes had been able to observe, under water. 

 " Swimming with its wings half expanded, though locomotion is 

 effected entirely by the feet, the bird pursues his prey (small 

 fishes) with a peculiar darting or jerking action of the head and 

 neck, which may be compared to that of a man poising a spear or 

 harpoon before throwing it. Arrived within striking distance, the 

 darter suddenly tranfixes, in fact, bayonets, the fish on the tip of 

 its beak with marvelous dexterity, and then immediately comes to 

 the surface, where the fish is shaken off the beak by jerking of the 

 head and neck (repeated until successful), thrown upward, and 

 swallowed, usually head first." A study of the neck in the re- 

 cently dead bird leaves little doubt as to the mechanism by which 

 this peculiar impaling of the prey is effected. The eighth cervi- 

 cal vertebra is articulated with the seventh in such a way that the 

 two cannot naturally be got to lie in the same line, but form 

 an angle, open forwards, of about 145 , when the two bones 

 are stretched as far as possible in that direction. After further 

 describing the mechanism, Mr. Forbes thus concludes his paper : 

 " It is obvious that considerable advantage is gained by the ac- 

 tion in question, the rapid protrusion of the narrow neck and head 

 over a small space by this mechanism necessitating a less amount 

 of exertion than would a similar movement of the whole bird over 

 the same space, and being equally efficacious in striking the prey. 

 The whole mechanism, it may be observed, exists in a less devel- 

 oped form in the neck of the herons, cormorants, etc.; and it re- 

 quires but a slight modification of the arrangement of these parts in 

 those birds — none of which, so far as I know, impale their prey like 



