A LAND PLANARIAN WITH AN ABNORMAL 



NUMBER OF EYES^'" 



The land planarians which are relatively common in the 

 tropical regions have few representatives in the temperate 

 zones, only two species thus far being known from Amer- 

 ica north of Mexico, with the exception of the introduced 

 form, Placocephalus kewense (Moseley) occurring in the 

 hot houses. These are Rhync hod emus sylvaticus (Leidy) 

 and Khynchodemus atrocyaneus Walton, the latter rep- 

 resented by only two specimens and the former by ten 

 specimens all belonging to the collection of the Depart- 

 ment of Biology, Kenyon College. It is therefore of 

 interest to record a specimen belonging to the former 

 species which possesses two pairs of eyes instead of the 

 normal single pair. The individual was among five col- 

 lected July 4, 1904, under the partially decayed stem of a 

 Virginia Creeper — Arnpelopsis quinque folia, and the 

 peculiarity was not noted until sometime later when 

 cleared in cedar oil preparatory to sectioning. 



The two pairs of eyes are nearly normal in position, the 

 anterior pair being 0.26 mm. and the posterior pair 0.33 

 mm. from the tip of the head in the preserved specimen 

 fixed in hot sublimate alcohol (Apathy) and somewhat 

 contracted. The anterior pair is nearly twice the diameter 

 of the others. No peculiarities of this nature have thus 

 far been noted among land planarians although vonGraff 

 ('99) in his monograph briefly discusses certain variations 

 in other organs. 



It is of interest to extend the range of our land planar- 

 ians and those engaged in work in Invertebrate Zoology 

 should be able to find them, particularly on summer 

 mornings after a rain, under partially decayed boards on 

 lawns, in orchards, etc., in company with young snails 

 which they superficially resemble. 



"Reprinted from The Ohio Naturalist, vol. 15 (1915), pp. 498-499. 



