86 THE NAUTILU:^-. 



species above nauierl, 3 others — Plaitorbis trivolvis Say, common, 

 FlsidUtm abdifain Hald., rare, and a Valv(da, which I suppose to be 

 virens Tryon, 6 specimens only. 



No Phijsa of any kind were observed, nor has Dr. Bean as yet 

 found any species of Unio, A)iodonta, or Sphcrrinm. 



The land shells enumerated below were all found under logs or 

 under pieces of board in the neighborhood of the settlement and 

 along the banks of the rivers. Vltriiia Umpida Gould, Hyalina 

 arhorea Say, Hyalina radiatula Alder, Coitulns fulvus Drap., Patula 

 strlatella Anth., Vallonia costata Miill. (form grac'dk-oda Reinh., 

 teste Sterki), Ferussacia saheylindrica Linn., Succinea avara Say, 

 and a species of Vertigo closely resembling gouldli, were all com- 

 mon. 



Papa hoppii MoUer, was not very common in the spots I searched 

 and I only secured 8 specimens. Still less frequent was Pupa alti- 

 cola Ingersoll, which I had here the pleasure of finding for the first 

 time. 



Dr. Baan has in his collection, besides the above, specimens of 

 Pupa pentodou Say, which he took a few miles to the west of Lag- 

 gan ; and a second species of Succinea perhaps S. ovalis Gould. 

 Lastly some slugs which were probably Lima.v hyperhoreus West., 

 were observed by us but not collected. 



The altitude of Laggan is about 5,200 feet above sea level and the 

 locality is interesting, as being nearly at the summit of the Rocky 

 Mountain range, which seems to form, in Canada, a hard and fast 

 line of demarcation between the eastern and western species of Mol- 

 lusca. 



H^ECKEL'S PLANKTONIC STUDIES. 



All interested in the life of the open and deep sea, the so-called 

 pelagic or Plankton fauna, will be interested to read the translation 

 of Prof E. Hseckel's paper of 1890, which is printed in the Report 

 of the U. S. Fish Commission for 1889-91, pp. 565-641. 



Some of the German polemics are omitted, though a sufficient 

 amount remains to spice the article in a lively manner. There is 

 much reason to believe that Hieckel, who has had no exi:)erience in 

 deep sea work, has overestimated the evidence in favor of zonary 

 distribution of life in the deep sea. Certainly the observations of 



