216 



SCIENCE. 



[N.. S. Vol. XIX. No. 475. 



Divisions of the Nervous System: J. B. 



Johnston, University of West Virginia. 



(Read by title.) To be printed in the 



Journal of Comparative Neurology and 



Psychology. 

 The Vascular System and Blood Flow in 



Diplocardia comvfiunis Garman: Peank 



Smith and J. T. Barrett. 



Diplocardia communis is a species of large 

 earthworms that are abundant in Illinois 

 and that have a vascular system which may 

 be profitably studied for the light thrown 

 on disputed points concerning the blood 

 flow of other species. Posterior to VI. the 

 dorsal vessel is double in each somite. In 

 IX. to XIV. there is a distinct supra-in- 

 testinal vessel which at its extremities joins 

 the vascular plexus of the oesophageal wall 

 and is connected with it by several short 

 branches in each of the somites X., XI. and 

 XII. There is nothing peculiar about the 

 ventral vessel. A subueural and lateral- 

 neurals are absent. A pair of lateral- 

 longitudinal vessels connects anterior 

 capillaries with the oesophageal plexus of 

 somites IX. to XIII. inclusive. From it 

 they extend outward to the body wall and 

 posteriorly along the latter in the clitellar 

 regions (XIII.-XVIII.). Three pairs of 

 dorso-intestinal hearts in X.-XII. force 

 blood from the dorsal and supra-intestinal 

 into the ventral. Paired dorsal hearts in 

 V.-IX. force blood from the dorsal into the 

 ventral. In each somite posterior to XX. 

 one to three intestino-tegumentaries connect 

 the intestinal wall with each dorso-tegu- 

 mentary at points near the body wall. Ob- 

 servations of pulsations and of the results 

 of clamping and cutting vessels have led to 

 conclusions of which the following is a brief 

 summary: In D. communis the blood flows 

 anteriorly in the dorsal; anteriorly in the 

 ventral in front of the hearts and poste- 

 riorly back of them; posteriorly in the 

 lateral-longitudinals into the oesophageal 

 plexus of IX.-XIII. and then partly into 



the supra-intestinal and ' partly to 'the 

 clitellar regions. Blood flows outward 

 from the ventral through ventro-tegument- 

 aries to the body wall, nephridia, nerve 

 cord ; and through ventro-intestinals to the 

 intestine. Blood flows into the dorsal from 

 the intestine through the dorso-intestinals 

 and from the body wall, nephridia, etc., 

 through the dorso-tegumentaries. Through 

 the intestino-tegumentaries ■ blood flows 

 from the integument to the intestinal wall. 

 These results closely accord with those of 

 Johnston and Johnson on Lumbricus ter- 

 restris as far as the vessels correspond, and 

 differ materially from those of other ob- 

 servers on that and other species. 



'*The Diffusion of North American Hawk 

 Moths: F. M. Webster, Urbana, Illinois. 

 The paper shows the probable northern 

 trend of diffusion from the tropics through 

 the Antilles into Florida, and through Cen- 

 tral America and Mexico into the south- 

 western and Pacific Coast states, or from 

 Honduras into the West Indies and thence 

 to Florida, and their diffusion from these 

 points of entrance into the United States 

 over North America. 



*Insect Life above Timber Line in Colo- 

 rado and Arizona: Francis H. Snovt, 

 Lawrence, Kansas. To be published in 

 the Kansas University Science Bulletin. 

 This paper calls attention to the differ- 

 ence in the character of insect life in the 

 two locations. In Colorado the species 

 above timber are generally peculiar and, 

 for the most part, not found below timber 

 line. In Arizona the species above timber 

 line do not differ from those below timber 

 line. Illustrations are given. The reason 

 suggested is that the glacial ice mass did 

 not extend to the Arizona summits. 



*The Salmonidce and Thymallidce of 

 Alaska: Barton Warren Evbrmann, 

 Washington, D. C. (Read by title.) 



