272 



THE AMEBIC AX X AT V RATI ST 



[Vol. LII 



clear that among dicotyledons and petaliferous monocotyledons 

 new types are produced and old types lost much more quickly 

 than anywhere else in vascular plants, a fact which in the light 

 of our knowledge of methods of reproduction certainly supports 

 the view that hybridization has 'been a powerful factor in evo- 

 lutionary change. 



Summary 



Evidence from a comparative study of endemism in various 

 elements of certain insular floras tends to show that among cross- 

 fertilized types new species are developed more rapidly and old 

 ones lost more frequently than among self-fertilized types, thus 

 emphasizing the importance of hybridization as a factor in evo- 

 lutionary change. Edmund W. Sinnott 

 Connecticut Agricultural College 



A LAND PLAXARIAX FOUND AT BERMUDA 1 

 In 1902 Professor Yerrill recorded (''The Bermuda Islands," 

 p. 436, Fig. 237), that there had been reported to him the find- 

 ing at Bermuda of a "worm" which appeared to be a land 

 planarian. With the possible exception of this worm, which may 

 have been a Bipalium, no land planarians have been seen at 

 Bermuda. While collecting earthworms, in September, 1917, I 

 obtained among moist decaying leaves in a "fertilizer pit" at 

 Point Shares, Pembroke Parish, a single specimen of a flatworm 

 which seems to be a species of Geoplana. The "pit" was in use 

 as a dumping ground for garden refuse, and since no laud plana- 

 rians appear to be native to Bermuda, the worm may have been 

 introduced in company with plants. It was 50 mm. long and 

 2 mm. wide, pale greenish blue on the ventral surface, — which 

 bore a rather small oral sucker in the u>ual position, — the ground 

 color of the dorsal surface being a deeper shade of the same 

 greenish blue, but marked with two deep blue or black longi- 

 tudinal stripes running the whole length of the animal. Two 

 well-developed pigment spots were present, one on either lateral 

 margin of the anterior end. It is not impossible that this species 

 might become permanently colonized at Bermuda (although no 

 other specimens have been found), and this note may therefore 

 be of use in fixing the date of its earliest observed appearance. 



W. J. Crozier 



Agar's Island, Bermuda 



