THE ANATOMY OP PENTASTOMUM TEEETIUSOULUM. 



and (3) descriptions and figures of the actual sections and 

 histological preparations, from a study of which the schematic 

 drawings have been deduced. 



To students, and those who are engaged in teaching, 

 schematic representations of the most diagrammatic nature 

 are, it appears to me, of great service. 



I am much indebted to my friend Mr. W. E. Hoyle for his 

 kindness in sending to me a copy of Leuckart's work, which 

 I was unable to refer to or procure in Australia, and also for 

 his kindness in supervising this paper whilst it was passing 

 through the press. 



The structure will be dealt with under the following heads : 



1. Habitat. 



The adult form lives in the lungs of the two snakes, Hop- 

 locephalus superbus and Pseudechys porphyriacus, 

 popularly known respectively as the '' copper-head" and the 

 " black " snake. The former is very common in certain parts. 

 In King Island it was not unusual to kill perhaps twelve to 

 twenty in the course of one day's tramp through the scrub. 

 I have myself as yet only found the parasite in the lung of two 

 specimens, and have never seen it save in King Island. On 

 one occasion Mr. McAlpine found it in the lung of a black 

 snake killed not far from Melbourne. 



In one copper-head, which to all appearances was perfectly 

 healthy and vigorous, and measured about 4 feet 6 inches in 

 length, there were no fewer than 129 specimens to be counted 

 in the lung and tracheal tube, of which some twenty were 

 males, the rest females, in various stages of growth. 



Each parasite lives with the whole of the head buried deeply 

 in the lung wall, and adheres so firmly by means of its hooks 



