﻿112 INTRODUCTION 



found that the ova within their uterine tubes had 

 undergone development, and still contained living 

 embryos ; indeed, some of these hatched under the 

 microscope, and moved very actively in the preserv- 

 ing fluid. This is in no way surprising, because 

 even after several years of preservation in formalin 

 solution the embryos of other species of eelworms 

 {Ascaris equorum, A. marginata) have been found in 

 a living condition. 



Trematoda. — The Flukes (Trematoda) of snakes, 

 so far described, belong to the following genera : 

 Agamodistomtim, Astiotrema, Brachylaimus, Cotylo- 

 tretus, Dicroccelium, Diplodiscus, Distomay Halipegus, 

 Lecithodendrium, Metorchis, Opisthogonimus, Opis- 

 thorchis, Plagiorchis, Saphedera, Telorchis, Tetracotyle, 

 Zeugorchis. 



Cestoda. — Save a few larval forms (Cysticercoides, 

 Piestocystis, Sparganum), the known tapeworms 

 (Cestoda) of the Ophidia belong to the genera 

 Bothridium and Proteocephahis, 



Protozoa. — Numerous species of Hsemogregarines 

 have been described from snakes. As a rule the 

 forms seen in the peripheral blood are sporonts, the 

 schizogonic cycle occurring in the lungs. The 

 sporonts do not greatly alter their host cells ; they 

 are invariably doubled up within a more or less 

 thick capsule. Some species show a marked sexual 

 differentiation, others not. Trypanosomes, Spiro- 

 echaudinnicBy and Plasmodidce have also been de- 

 scribed from the blood of various snakes. 



