Some Stages in the Development of Œsophagostomum dentatum from the Pig

Abstract

In an earlier paper (Goodey, 1924), the writer has given an account of the morphology of the adults of Œsophagostomum dentatum, the development and structure of the free-living larvæ and the biology of the ensheathed infective stage. So far, however, the parasitic larval stages have not been described. In the present paper some of the gaps in our knowledge of the complete life-history of the worm represented by these stages are filled in, not as completely as could be desired owing to the absence from the material of specimens showing the 3rd and 4th ecdyses. The worms found, however, show that the 4th stage larva has a provisional buccal capsule essentially similar to that found in 4th stage larvæ of O. radiatum (Marotel, 1908) and O. columbianum (Veglia, 1924), and in this respect is in line with certain other 4th stage larvæ of the Strongyloidea such as Ancylosloma duodenale (Looss, 1897), and Triodontophorus tenuicollis (Ortlepp, 1925), in which provisional buccal capsules built on the same general plan have been observed.