THE NAUTILUS. 91 
The authors begin with the new Gasteropod Miratesta celebensis, 
for the reception of which it seems necessary to establish not only a 
new genus, but a new family (Miratestide). The structure, which 
is briefly described, shows a combination of characters distinctive of 
various families. The animal is nearest the freshwater Pulmonates, 
especially the Limnzeide, as is suggested by the Planorbis-like 
structure of the radula, the nervous system without chiastoneury, 
the hermaphroditism, and the absence of an operculum. But any 
very close affinity is impossible, as is shown by the large gills, the 
very peculiar pouched feelers, and the structure of the shell. Dis- 
tant relations may, perhaps, be found in the so-called Thalassophilze 
(Amphibola and Siphonaria). In any ease, the family is phylo- 
genetically old, near the base of the freshwater Pulmonates. 
Bulletin 142 U.S. Geol. Survey, 1896, contains a valuable paper 
upon the geology and paleontology of northwestern Louisiana by 
T. Wayland Vaughan. A number of new mollusks from Lower 
Claiborne and Jackson stages of the Eocene are described and fig- 
ured. 
Mr. Charles Schuchert has given a very useful “Synopsis of 
American Fossil Brachiopoda, including Bibliography and Syn- 
onymy ” in Bull. No. 87, U. S. Geol. Survey, 1897. The geological 
distribution, terminology, biological development and classification 
are discussed, and a valuable chapter contributed by Prof. Charles 
E. Beecher treats of the morphology of the brachia, a subject which 
in Beecher’s hands has assumed great importance as an index of 
phylogeny and rank. 
Mr. Félix Bernard has given a very thorough account of the 
anatomy of Chlamydoconcha Oreuttt Dall, in Annales Sciences 
Naturelles (zool.), iv, 1896, pp. 221-252, with 2 plates. 
A NEW PLICATE UNIO. 
BY BERLIN H. WRIGHT. 
Unio Walkeri sp. noy. 
Shell solid, ovate, inflated at the umbos, rough, plicate-nodulose 
on posterior slope and indistinctly so anterior to the umbonal ridge; 
gradually fading out near the centre of the disk. Umbonal ridge 
uniformly rounded below and sharply angulate above. Epidermis 
nearly black; transmitted light showing a light-colored texture. 
Very faintly marked anterior to the umbonal angle with broad, 
widely separated, interrupted rays. Posterior margin bluntly 
rounded or somewhat disposed to biangulation, uniformly rounded 
before, dorsum arcuate, base nearly straight or emarginate, cavity 
uniform, moderate and scarcely extending under the dorsal plate. 
Teeth solid, single in the right and double in the left valve. Ante- 
rior cicatrices barely distinct. Thinner behind, showing the plica- 
