86 THE NAUTILUS. 
species above named, 3 others—Planorbis trivolvis Say, common, 
Pisidium abditum Hald., rare, and a Valvata, which I suppose to be 
virens Tryon, 6 specimens only. ; 
No Physa of any kind were observed, nor has Dr. Bean as yet 
found any species of Unio, Anodonta, or Sphwrium. 
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. Vitrina limpida Gould, Hyalina 
arborea Say, Hyalina radiatula Alder, Conulus fulvus Drap., Patula 
striatella Anth., Vallonia costata Mull. (form gracilicosta Reinh., 
teste Sterki), Ferussacia subcylindrica Linn., Succinea avara Say, 
and a species of Vertigo closely resembling gouw/dii, were all com- 
mon. 
Pupa hoppii Moller, 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. Bean has in his collection, besides the above, specimens of 
Pupa pentodon Say, which he took a few miles to the west of Lag- 
gan; and a second species of Suceinea perhaps S. ovalis Gould. 
Lastly some slugs which were probably Limax hyperboreus 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- 
lusea. 
HECKEL’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. Heckel’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 sufticient 
amount remains to spice the article in a lively manner. There is 
much reason to believe that Heckel, who has had no experience in 
deep sea work, has overestimated the evidence in favor of zonary 
distribution of life in the deep sea. Certainly the observations of 
