April 11, 1913] 



SCIENCE 



567 



ties, from those which prevailed in the insti- 

 tutions when they were undergraduate or 

 graduate students. But it is believed that 

 the figures given above approximately repre- 

 sent the influence of the several institutions 

 upon the general trend of thought in agricul- 

 tural science. 



Of the 54 other degrees granted to members 

 of this society, not more than three came from 

 any one institution. In these computations 

 no account has been taken of honorary de- 

 grees, only those granted for completion of 

 prescribed work having been counted. 



It is perhaps of interest to note that the 

 147 men who have been on the membership 

 roll of this society during the past five years 

 have received 128 bachelor's, 82 master's and 

 51 doctor's degrees earned by undergraduate 

 and graduate study. While statistics as to 

 the scholastic attainments of workers in other 

 . educational fields are not available for com- 

 parison, it appears to the writer that the 

 scholastic training and ability of the men who 

 are actively engaged in the promotion of agri- 

 cultural science is certainly such as to com- 

 mand very high respect. 



E. W. Thatcher 



State College of Washington, 

 Pullman, Washington 



SPECIAL ASTICLES 



THE DISTRIBUTION OP OCCIDENTAL SPIDERS 



A PERFECT knowledge of geographic distri- 

 bution can not be had until we have good col- 

 lections with good field notes from all im- 

 portant regions and a perfect taxonomy. That 

 time is far distant. Meanwhile we can get 

 some indications from the material at hand. 

 One of the interesting problems concerning 

 the relations between the two continents of 

 the western hemisphere is the part, if any, 

 which the West Indies has played in geo- 

 graphic distribution. 



Spiders being carnivorous, and so probably 

 not limited in their distribution by the distri- 

 bution of special food, and being unable to fly 

 or swim great distances, seem to offer excel- 

 lent material for such a study. Unfortu- 

 nately large collections have not been made 



and the taxonomy is rather chaotic. Omit- 

 ting a number of genera either because of in- 

 definiteness of information as to distribution 

 or obvious errors in taxonomy, there still re- 

 main in Petrunkevitch's catalogue' 764 genera . 

 of spiders found in the western hemisphere. 

 The distribution of these is analyzed to some 

 extent in the table. While 119 of these gen- 

 era are recorded as occurring in both South 

 America and the United States, it is probable 

 that there would be more were it not for the 

 tendency to magnify taxonomic differences 

 when political boundaries are crossed. It is 

 somewhat surprising, in view of the usual 

 notion that insular conditions lead to taxo- 

 nomic separation, to find that only 14 per 

 cent, of the West Indian genera are not found 

 in neighboring regions, while 60 per cent, of 

 the South American do not occur elsewhere. 

 Even 22 per cent, of the Central American 

 (Mexico being included) genera are not re- 

 corded as occurring in the adjacent regions. 



Distribution of Genera of Spiders. Bold-fa<:ed 



type shows actual numbers; ordinary 



type, percentages. 



Total 



Exclusive^.. 



S. A., C.A.. 



S. A., W. I. 



S. A., U. S., 



C. A.,"\V. I 



C. A., U. S. 



W. I., U. S 



All four 



240 



90 



37.5 



36 



15.0 



7 



2.9 



30 



12.5 



3.3 

 20 



3 



1.3 



19.2 



^ A. Petrunkeviteh, ' ' A Synonymic Index-cata- 

 logue of Spiders of North, Central and South 

 America with all Adjacent Islands," Bull. Amer. 

 Museum Nat. History, Vol. XXIX., 1911. 



- In the sense that they are not recorded from 

 any of the other regions considered here. 



