DESCRIPTIONS OF FOUR DISTOMES. 31 



IV. RENIFER VARIABILIS (LEIDY) LUHE. 



Three specimens of this worm were found in the lung of Tropidonotus sipedon, a 

 common non-poisonous snake. In 1856 Leidy ('56, p. 44) described very briefly 

 two distomes which he named Distomum variabile, Variety a and Variety b. His 

 description was as follows : 



" Var. a. Body white, variegated with black in the course of the oviduct, 

 clavate, posteriorly obtuse, minutely echinated." "Oral and ventral acetabula 

 nearly equal; the latter one prominent, situated at the base of the neck. Length to 

 6 lines; breadth of body - a line." "Attached to the sides of the cavity of the lungs 

 of Tropidonotus sipedon." 



" Var. b. Body flattened, ovate, continuous with the head, anteriorly narrowed, 

 posteriorly obtuse, color and echination as in the preceding variety. Length 2^ 

 lines; breadth 2 lines." Found detached in the mucus of the lungs and trachea of 

 Tropidonotus sipedon. 



Variety b has also been described, briefly and without figures, by Max Liihe 

 (:00, p. 559), who obtained his specimens from the Museum fur Naturkunde in Berlin. 

 Ltihe proposes to confine the specific name variabile to this worm and to consider 

 Variety a a distinct species. 



Although the worm found by me differs in some slight degree from Distoma 

 variabile as described by Liihe, I have no hesitation in ascribing it to that species. 

 The following is a description of it. Renifer variabilis (PL IV, Fig. 5) is a broad, 

 flat worm between 3 millimetres and 4 millimetres in length and between 1.50 milli- 

 metres and 2 millimetres in width; the average thickness is 0.5 millimetre, the dorsal 

 and the ventral surfaces being approximately parallel. The greatest width is just 

 posterior to the middle of the body, from which region it tapers towards the anterior 

 end, while the hinder end is rounded and semicircular in outline. The entire body 

 is thickly set with minute spines which are arranged anteriorly in rows and are more 

 numerous there than posteriorly. Liihe found only the anterior portion of the 

 worm examined by him to be covered with spines, but it is not impossible that the 

 spines had been present on the hinder portion, but had disappeared as a result of 

 poor preservation, for the worm was an old museum specimen. The suckers are 

 of good size and are sessile. The oral sucker is subterminal and has a diameter of 

 0.5 millimetre in a large specimen. The acetabulum is about 0.4 millimetre distant 

 from the oral sucker and has a diameter of 0.6 millimetre in a large animal. The 



