REPTILES, RATRACHIANS, AND FISHES. 41 
if circumstances permit, is better preserved in spirit than dry. Of 
course the head requires then no further preparation. 
Large Pythons and Boas are so frequently brought to Europe alive 
that most museums have opportunities of obtaining good skeletons; 
and therefore it is not worth while for a traveller to preserve them, 
unless they are of a size to verify reports in which Pythons exceeding 
25 feet and Anacondas of over 30 feet are mentioned. 
The attention of the traveller may be called to a few other points. 
The determination of the large River-turtles ( Trionyx ) which 
inhabit the fresh waters of Asia and Africa is a matter of con¬ 
siderable difficulty and uncertainty, which cannot be dispelled except 
by collecting afresh large numbers of all the species without ex- 
i ception. The traveller should try to obtain as many specimens as 
possible of all ages, with their exact localities, and always with the 
skulls. It would also be particularly interesting to receive specimens 
t taken in copuld. 
Collecting Sea-turtles seems little likely to lead to important 
results. However, very large specimens of the Leathery Turtle 
( Dennochelys ), and more especially its skeleton, are much sought for 
by museums. It would also be important to obtain embryos in the 
t shell in different stages of development.* 
Comparatively little is known at present of the habits and mode 
i of reproduction of Lizards ; and when the traveller has an opportunity 
of observing any of these animals for some time, he should note down 
i everything which appears to him remarkable. 
Of Snakes it is urgently recommended that the small and obscurely 
i coloured species should be searched for. Many of these live habitually 
underground, or are nocturnal animals which can only be obtained 
by digging up the soil or by searching for them among decaying 
substances. The Sea-snakes are very numerous in species and 
varieties, and should receive special attention. The collector should 
obtain all the specimens he can (except the common Platurus 
and Hydras '); but he must be careful to note the exact locality, 
* Embryos of all species which are enclosed in egg-shells should be preserved 
in the strongest spirit, after several holes have been pierced in the shell, in order 
1 to empty it of the fluid portion of its contents. 
