34 THE NAUTILUS. 



Academy are to be congratulated upon the success with which the 

 undertaking has been carried out. 



Beginning with the Pulmonala, the Umd species, 51 in number, 

 are first described, a sutRciently full synonomy of each is given with 

 figures of the shell, and in nearly all cases of the jaw and radula. 

 Full details of local distribution and of the habits and characteristic 

 peculiarities of the different forms are also given. Pilsbry's classi- 

 fication is of course followed, and the whole treatment of the subject 

 is in accordance with the latest scientific methods. 



Tiie most striking innovation in this portion of the work is the 

 adoption of Say's name of ovalis for the species commonly known as 

 Succinea obliqua. This is, however, in accordance with the recog- 

 nized rules of nomenclature, and it is surprising that it has not been 

 done before. The Succineas need a thorough revision. The specific 

 characters exhibited by the shells are slight, and most of the de- 

 scribed species seem to be exceedingly variable. It is possible that 

 dissection will show reliable characters in the soft parts that can be 

 relied on for specific determination. This work has yet to be done 

 and would be a very valuable contribution to science. The jaws and 

 raduloe if examined in sufficient quantities to determine the amount 

 of variability in each species, might furnish a sufficiently reliable 

 basis for classification. The difi^erence shown between the author's 

 figure of S. ovalis and Binney's figure of that of S. totteniana and 

 that between his figure of the radula of ovalis and Binney's figure of 

 the same, and the remarks on the same subject with reference to the 

 published figures, the jaw of S. rehtsa is very suggestive, and shows 

 the necessity for additional work in that line. It is unfortunate that 

 the author did not make an original figure of the jaw of S. avara, as 

 there is reason to believe that Morse's figure, adopted by Binney, is 

 not correct. 



The treatment of the fluviatile univalves is a welcome addition to 

 the scanty literature on the subject. The only regret is that the 

 fauna of the Area is comparatively small and that so many of our 

 common species are not represented in it. 



The keys supplied under the different genera serve to bring out 

 the differential specific characters, and will be of great assistance to 

 the student in identifying his specimens. The jaws and radulae of 

 many of the species are figured for the first time and many anatomi- 

 cal details of value are given. This branch of the subject is practi- 



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