636 Descendenz und Hybriden. — Morphologie und Teratologie. 



for regarding these cases as illustrations of „False hybridism" 

 or monolepsis. W. Bateson. 



Mayer, A. G., Effects of Natural Selection and Race- 

 Tendency lipon the Colour-Patterns of the 

 Lepidoptera. (Science Bulletin of the Brooklyn Institute. 

 Vol. I. No. 2. 1902 and London 1903.) 



An elaborate study is made of the markings on the wings 

 of 1173 species of Lepidoptera, 453 of Papllio, 30 of Oml- 

 thoptera, 478 of Castnia, and 643 of various Hesperidae. The 

 typical pattern of each species is analysed, and expressed in 

 terms of the numbers of spots or stripes of colour, the number 

 of rows into which colour-spots are arranged, and so on. If 

 any one character, such as the number of rows of spots, be 

 followed through an entire genus e. g. Papllio, a diagram may 

 be constructed, showing the number of species in which any 

 given number of rows of spots occurs; such a diagram is found 

 to show that the mean specific characters group themselves 

 about a „modal" value (a value of maximum frequency among 

 species of the genus) in much the same way as individual 

 variations, observed within the limits of a species, are found to 

 group themselves about a modal value. In many cases, 

 however the distribution of characters among the species studied 

 by Mayer was probably bimodal. 



Since the modal frequerrcy corresponds to roughly the 

 same value of several characters in species of Papllio (and of 

 other genera) from different geographica! areas, and since the 

 characters studied often seem to the author of Iittle protective 

 or other value, it is argued that the observed predominance of 

 a „modal" character among the groups of species cannot be 

 due either to natural selection or to environmental influence; 

 it is therefore attributed to a „race-tendency" such as that 

 invoked by Eimer and his pupils in similar cases. No attempt 

 is made to establish either a phylogeny of the groups studied, 

 or a theory of inheritance, which would lead to the observed 

 results, and no experimental evidence is adduced to show 

 whether natural selection or any other modifying influence is 

 in fact affecting any one of the species examined. 



K. Pearson. 



BOWER, F. 0., Ophloglossum slmplex R i d 1 e y [non Rumph]. 

 (Ann. of Bot. 1904. pl. XV.) 



This new species was discovered by Ridley near Siak, 

 in Sumatra. It differs from other species of the genus in the 

 entire absence of the vegetative lamina, as observed from 

 without. The anatomical investigation (conducted on a Single 

 herbarium specimen and therefore open to confirmation or 

 correction when more material shall be available) led to the 

 following conclusions. Structurally the plant resembles P. pen- 

 dulum, not only in the arrangement and connections of the 



