188 



THE AQUARIUM, JULY, 1895. 



a pretty clear illustration of this 

 method. The figure in the distance 

 shows the comparative height and size 

 of the tanks. 



As will be seen, only the front of 

 each tank faces the observer. He can 

 see all that should be seen and is abso- 

 lutely prevented from injuring the con- 

 tents. The display in such tanks can 

 be made very effective, it being possible 

 to arrange everything in proper focus. 



The screen or protective wall of a 

 •series of such tanks may be of any de- 

 sign. In connection with a floral dis- 

 play we found a rustic design best. A 

 cave-like or underground arrangement 

 is also very beautiful. The famous 

 Berlin Aquarium is built on that prin- 

 ciple altogether. 



FANGS OF SEEPENTS. 



The venomous serpents are divided 

 into two groups, namely, SoUnoglypha, 

 including the rattlesnakes, vipers, etc., 

 a,nd Proteroglyflia, embracing the cob- 

 ras, coral or bead snake {Flaps) and 

 venomous water snakes of the East 

 {HydrophidcB). Fortunately, harmless 

 serpents are, throughout the world, by 

 far the most numerous. In the States 

 north of Maryland, there are only two 

 species of jjoisoned-fanged serjaents 

 (the rattlesnake and copperhead), while 

 the non-venomous number eighteen 

 species. 



The fangs of serpents vary in num- 

 ber, shape and size. In the viper {Pe- 

 lias herus), the only venomous one of 

 the three species of serpents found in 

 Oreat Britain, the fangs are two in 

 number, and are situated in the super- 

 ior maxillary bones. There are no 

 other teeth in the maxillae, but there 

 is a row of small teeth in the palatine 

 bone on each side. The bite of the 



viper is often extremely painful, but 

 rarely, if ever, fatal. The viper is not 

 found in the United States. 



I remember on one occasion, in Mary- 

 land, a gentleman conducted me to a 

 wood to show me a " viper" he had a 

 short time before killed, and gravely 

 informed me that it was an "extreme- 

 ly dangerous species." It, however, 

 proved to be a harmless hog-nose snake 

 {Heterodon platyrliinus) . 



The fangs of the rattlesnake {Cro- 

 talus) are also two in number, situated 

 as in the viper. They are curved back- 

 ward, and hollow, save at the tips, 

 where they are solid, and turned 

 slightly forward. The minute opening 

 through which the venom is ejected is 

 in front, about one twelfth of an inch 

 from the needle-like point. The glands 

 in which the venom is secreted, are 

 oval and almond-shaped, two in num- 

 ber, situated on either side of the up- 

 per jaw, behind the eye. Each gland 

 has a duct connecting with the base of 

 its fang. These poison ducts are kept 

 closed by an arrangement of muscular 

 fibres when the fangs are not in use, 

 but at the moment when the snake 

 strikes, these ducts are forced open by 

 certain muscles of the head, and the 

 poison shoots through the ducts and 

 out of the openings near the points of 

 the fangs into the wound. When not 

 in use the fangs lie upon the gums in 

 the roof of the mouth, buried in the 

 folds of the mucous membrane. 



The deadly machuca of Nicaragua 

 (Botlivops at vox) has four great fangs 

 in the upper jaw, two on each side. 

 In view of the serious results which 

 have followed the bite of our Crotalus 

 and moccasin armed with only two 

 fangs, how much more deadly must be 

 the machuca, driving venom into four 

 wounds at once! 



