352 NOTES ON AUSTRALIAN LAND-PLANARIANS, 



placed just behind the anterior extremity and scattered sparsely 

 on the lateral margins of the body for its entire extent." 

 Accordingly in the list of the known genera and species of land- 

 planarians given in Mr. Moseley's valuable paper, he places the 

 planarian described by Darwin among the species of Geoplana, 

 with the remark that " this (species) will possibly prove allied to 

 the Australian genus Ccenojilana." Further in the same paper in 

 his description of Geoplana Traversii from New Zealand Mr. 

 Moseley says : " numerous eye-spots are present ; these are placed 

 in a single row composed of twelve or more along the front 

 margin of the head and in an elongate patch on either side of the 

 head made up of two or three rows placed one above another and 

 containing about forty eye-spots. Eye-spots are further scattered 

 more sparsely on the lateral margins of the body, along its entire 

 length posteriorly to this patch." Now in all our species with 

 numerous eyes this is substantially the condition that we meet 

 with. Thus in a young specimen of one of our species, G. 5-lineaia, 

 shortly after its emergence from the cocoon, and when it measured 

 about 4 mm. long and 1 mm. broad, it was easy to count all the 

 eyes, of which there were about 40 in each of the crowded patches, 

 two, three or even four deep, and these were connected antei'iorly 

 by a single closely set row of about 16, of which 7 Avere on the ^ 

 very tip of the anterior extremity ; posterior to the patches there 

 were about 20 on each side scattered at more or less considerable 

 intervals (1). The total number of eyes, as well as the numbers 

 of eyes and of rows of them in the crowded patches vary with the 

 the size of the animal, and appear not to be of specific importance. 

 They are very numerous in the adults of this species, which 

 sometimes show six or seven or even more rows of eye- 

 spots in the crowded patches extending upwards on to the 



(1) The actual number of eyes that can be counted just on the tip itself 

 varies of course with the amount of contraction of the body ; when fully 

 extended the anterior extren.ity of even a large planarian will hardly if at 

 all exceed 1 mm. in width, and then there may be only from three to five 

 eyes in this space. 



