THE NAUTILUS. 23 



not the case in Rhode Island, being extremely local, though abundant 

 where found at all. Up to October of 1872, it had never been col- 

 lected in this State. I had frequently examined our various ponds 

 and rivers with particular reference to this species, without success, 

 but in riding past Mashapang Pond one day in October, I noticed 

 that the water was extremely low, and on going down to the edge 

 of the pond I saw numerous tracks of Unios in the sand, and among 

 them were some which seemed a little different in shape from those 

 made by the U. complanatus. On following up these tracks (some of 

 them eight or ten feet in length) I found at the end of each, bur- 

 roAved in the sand, the long-looked for radiatus. 



Genus Margaritana, Schum., 1817. 



Shell transverse, inequilateral ; hinge like that of Unio, but des- 

 titute of lateral teeth. There are forty species, three of which in- 

 habit Rhode Island. 



(To be continued.) 



PUBLICATIONS RECEIVED. 



Third Supplement to Fifth Volume of Terrestrial 

 MoLLUSKS OF the United States. By W. G. Binney. (Ex. 

 Bull. :\Ius. Comp. ZooL, vol. xix, pt. 4, May, 1890.) This Third 

 Supplement equals our expectations, in fully sustaining the author's 

 reputation for careful and reliable work. In it are described 

 and figured the species of land mollusks made known since the 

 publication of the Second Supplement. Mr. Binney, while not de- 

 parting from that wise conservatism, in regard to specific limitations, 

 which has made his successive volumes models of careful systematic 

 work, devotes more space than formerly to the important subject of 

 variation. Geographical distribution also has much attention. 

 The species and varieties figured and described are as follows : Zonites 

 minusculus var. A lachuana Dall (Florida), Succinea chrysis and annexa 

 "Westerlund (Alaska), Zonites ligerus var. Stonei Pilsbry (Del.), Z. 

 Sterkli Dall (Ohio), Pupa Holzingeri Sterki (Minn., 111.), Zonites 

 Singleyanus Pilsbry (Texas), Z. Dallianus Simpson (Fla.), Micro- 

 physa f dioscorico/a Ad. (Fla.), Polygyra auriculata var. microforis 

 Dall (Fla.), P. Jacksoni var. deltoidea Simpson (Ind. Ter.), Mesodon 

 Kiowaensis Simpson (Ind. Ter.), Acanthinula granum Strebel & 



