288 REPIILES. 



The Sea or Pelagic Serpents (Hydrophidia] are not very numerous in 

 species, thirty-two only being described, but they are extremely abundant as 

 individuals, and, unlike the terrestrial serpents, are always met with in num- 

 bers together; so much is this the case in latitudes where they are common, 

 that their appearance serves to mariners as an indication that they are ap- 

 proaching land. Their body, in order more easily to cleave the waves, becomes 

 slender towards the two extremities, and their tail is so compressed or flat- 

 tened as to be at once an oar and a rudder. These snakes cannot erect their 

 fangs so much as the Viperine Serpents, and in biting their prey they retain 

 hold of it with their jaws. Their size varies in different species, from two feet 

 and a half to five feet. 



The Fresh-water Snakes (Homalopsina) * are nearly equal in number 

 to the marine, about thirty-six species being described. They are almost all 

 natives of intertropical countries, and have been met with in India, China, 

 Java, Borneo, the West Indies, and in the warm parts of North and South 

 America. Many of them attain considerable dimensions, but they rarely 

 exceed four feet in length, though they are as thick as a man's arm. The 

 greater proportion of them are truly aquatic, and appear particularly formed 

 for peopling the immense tracts of fresh water found in the countries they 

 inhabit, which swarm with fishes, that constitute their usual food. They have 

 a peculiar appearance and most disproportionate shape, a short, conical, and 

 robust tail, a head exceedingly broad, thick, blunt, and short, covered with 

 plates of irregular and inconstant form, small nostrils, and little eyes directed 

 upwards 



FAMILY II. VENOMOUS SERPENTS. 



The Second Family is that of the Venomous Serpents par 

 excellence, the most dreadful of all living creatures. Fortunately 

 there is something more than usually repulsive in their aspect : 

 their thick broad head, their wide jaws, their brilliant eyes, give 

 them an expression of diabolical malignity, and man and beast 

 instinctively recoil from their presence. Their general appearance 

 and physiognomy are so peculiar, and the impression which their 

 look creates is so vivid, that they may, for the most part, be imme- 

 diately recognized by any one who has ever attentively examined 

 a single species. " Their jaws are generally weak ; the under one 

 is provided with a series of sharp-pointed teeth, but the upper 

 jaw is destitute of any, except the moveable poison-fangs. The 

 head is extremely broad, flattened on the crown, and heart-shaped 

 or triangular. Instead of being covered by plates, as in the harm- 

 less races, it is clothed in scales similar to those of the back. Their 

 eyes are small, have a vertical pupil, are deep sunk in the sides of 

 the head, and overshadowed by the projecting plates of the eye- 

 brow. The upper lip is swollen, and hangs down in order to con- 



* 6jUaX6j, homalos, smooth ; 6'i/a?, opsis, appearance. 



