16 



SIXTEENTH REPORT. 



membranes usuall}" found covering eggs of this group. The third membrane, 

 if present, covered the yolk mass so closely that It could not be distinguished. 

 Hooks were not seen on any of the eggs examined hence it is probable that 

 the oncospheres were not fully formed. IMeasurements of the envelopes 

 and the j^olk masses of six eggs are given in the following table: 



Outer membrane 



0.057 mm. 

 0.060 mm. 

 0.067 mm. 

 0.057 mm. 

 0.057 mm. 

 0.067 mm. 



Second membrane 



0.033 mm. 



0.035 mm. 



0.033 mm. 



0.033 mm. 



0.027 mm. 



0.037 mm. 



Yolk mass 



.0.023 mm. 

 0.033 mm. 

 0.030 mm. 

 0.030 mm. 

 0.025 mm. 

 0.033 mm. 



0.0608 mm average. 



0.033 mm. average. 0.029 mm. average. 



In securing the above eggs for measurement a few volk masses were teased 

 out of the egg-membranes. These measured 0.20, 0.023, 0.02, 0.017, 0.02, 

 0.02, 0.023 mm., average 0.020 mm. On account of the fact that the egg- 

 membranes make it difficult to determine the limits of the yolk mass it is 

 probable that the measurements of the membraneless yolk masses are 

 more accurate than those given in the third column of the table. 



RELATIONSHIPS 



This species is clearly a member of the genus Ophiotaenia. Its nearest 

 congeners are the two species of Ophiotaenia already known to inhabit 

 certain tailed amphibians of North America, viz. 0. filaroides La Rue from 

 Ambystoma tigrinum (green) and 0. lonnbergii (Fuhrmann) from Nedurus 

 7naculosus Raf. With these two species it forms a well graded series in size, 

 this species being the larger (as is also its host). In respect to size and to 

 the relative position of the vagina and cirrus-pouch, ancl also in respect to 

 the sinuous vagina and the long slender protruded cirrus this species resem- 

 bles 0. lonnbergii more closely than 0. filaroides. 



It differs considerably from 0. hylae Johnston which is found in Hyla 

 aurea, New South Wales in size, position of the genital pore ancl the usual 

 relations of vagina and cirrus-pouch. The latter species more closely 

 resembles some of the reptilian Ophiotaeniae. 



BIBLIOGRAPHY 



Fuhrmann, 0. 1895. Die Tanien der Amphibien. Zool. Jahrb. Anat. 

 IX, 207-226, 1 pi. 



Johnston, T. H. 1912. Notes on some entozoa. Proc. Roj'al Soc. 

 Queensland, XXIV, 63-91, 3 pi. 



La Rue, G. R. 1910. On the morphology and development of a new 

 cestode of the genus Proteocephalus Weinland. Trans. Amer. Microscopi- 

 cal Soc. XXVIIL 17-49, 4 pi. 1911. A revision of the cestode familv Pro- 

 teocephalide. Zool. Anz. XXXVUI, 473-482. 1914. A revision of the ces- 

 tode familv Proteocephalidae. Illinois Biological Monographs I, Nos. 1 and 

 2, 350 pp.,"^ 16 pi. 



Riggenbach, E. 1896. Das Genus Ichthyotaenia. Rev. Suisse de Zool. 

 Geneve IV, 165-275, 3 pi. 



