THE NAUTILUS. 59 



areas entirely or quite imperfectly unrepresented in the older 

 collections have been explored. More intensive work and better 

 methods of collecting have resulted also in a great increase of 

 species known from the older States. Most of the material col- 

 lected in recent years has been studied by Dr. Sterki, who has 

 now given us a systematic catalogue, with distribution, synony- 

 my and descriptions of new forms. The recent species admitted 

 by Sterki and b}' Prime number as follows: 



Sphaerium Musculium Eupera Piddium 

 Q, 1- f Species . . 31 23 2 88 



^^^^^^ (Subspecies .8 9 49 



Prime. Species. . . 17 13 1 17 



While there has been great increase in all the genera, during 

 the past 50 years, Pisidhim has been enlarged far more than 

 the genera of Sphaeria, in which specific characters are more 

 obvious. To conchologists Pisidiinn is much what Crataegus is 

 to the botanists. 



A classification into subgenera is given on pages 472-4. The 

 subgenera Lacustrina (type Pisidium idahoense) and Fontinalina 

 (type P. fontinale) are new. We may inquire whether authors 

 who give preference to the principle of tautonymy in type 

 selection (International Rules, Art. 30, I, d) would consider 

 Cyclas cornea the type of Corneocyclas F6r,, which in that case 

 would replace the subgenus Corneola Clessin. Dr. Sterki has a 

 monograph of the American Spha'riida^ under way. Until this 

 is published, conchologists will find the present catalogue in- 

 dispensable. — H. A. P. 



Some Directions and Suggestions for collecting the 

 Sphaeriid.e and Aquatic Gastropods. By Victor Sterki, 

 M. D. This paper, following the preceding, will be found 

 useful by all conchologists collecting freshwater shells, as it gives 

 the methods which have proved most effective. 



A Trip to Islands in Lake Erie. By Calvin Goodrich 

 (Annals Carnegie Mus. X, 1916, pp. 527-531). 



The record of a collecting excursion made by Dr. Clapp, Dr. 

 Bryant Walker, Mr. Lucas Beecher and the author in July, 1915, 



