THE NAUTILUS. 69 



was sifted through a small net and the sittings were worked over 

 after returning home. 



In both Panuco and Taniesi rivers there seemed to be very little 

 molluscan life. Nearly all the living fresh-water forms listed from 

 Tampico were taken from small ponds near LaBarra. 



The mouth of the Panuco river is protected by jetties, on the gulf 

 side of which most of the living marine species were taken. Not a 

 specimen of any species was noticed on the river side of the jetties. 

 Two days were spent on the beach and jetties, but no other effort 

 was made to secure the marine forms. 



In the vicinity of Valles the land shells were no more plentiful 

 than about Tampico, but the Valles river was much richer in both 

 species and individuals than the rivers at Tampico. With two ex- 

 ceptions the small streams seemed destitute of molluscan life. 



It has been thought desirable to publish the full list because the 

 shell fauna of this part of Mexico is but little known. No informa- 

 tion has before been published on the marine forms between Texas 

 and Vera Cruz ; and the only data on the land shells of the region 

 is contained in Pilsbry's paper on Rhoads' collection, which was 

 made somewhat further inland, north of the localities here dealt 

 with. It is likely that some of the old species hitherto credited to 

 Texas were really taken at or near Tampico, such as Helicina 

 chrysocheila and Euglandina corneola. The occurrence of Adelo- 

 poma so far north is remarkable. 



The larger part of the species of this list were passed on by Dr. 

 H. A. Pilsbry. Thanks are also due to Dr. Wm. H. Dall for as- 

 sistance with some of the marine and fresh-water forms. 



MARINE MOLLUSKS. 



Spirula spirula (L.). Only broken ones taken. . 



Ostrea sp. Scattering young were on the jetties. In different 

 places along the river and canal are beds of oyster shells exposed 

 to view, overlaid by the surface soil. These shells are often dug 

 out and burnt for lime. 



Chama arcinella L., odd valves. 



Pecten exasperatus Sby., odd and broken valves, common. 



Pecten gibbus irradians Lam., odd valves. 



Pecten nodosus Linn., broken valves. 



Pecten raveneli Dall (?), one lower valve. 



