Review of liecetit Geological Literature. 349 
Ten new species of Ci/rtodonta are described from Minnesota, in this 
volume, besides five others previously recorded by the author from the 
same state, in the "19th Ann. Rep. Geol. and Nat. Hist. Surv., Minne- 
sota," for 1893. Forms referable to Vanuxemia Billings, but oftimes 
referred to C ypricardites by .United States writers are also noted. 
Under Matheria Ulrich places one Minnesota species: M. rugosa, Ulrich, 
whilst under his genus Whitella he places twelve forms at times very 
difficult to separate. 
Under the family Nuculid^e, Mr. Ulrich has made an interesting 
study of the shells referable to the genus Ctenodonia Salter. He has 
arranged the large array of species of this genus into "six more or less 
well marked groups" in which an attempt is made to classify most of 
the Noi'th American species from the limestones of the Quebec group of 
Newfoundland, as well as from the Lower Silurian rocks of Tennessee. 
We should have been pleased to have seen the mist dispelled which hangs 
over the genera Clidophorus, Cucullela and Nuculites. Without enter- 
ing upon the task, Mr. Ulrich classes two Lower Silurian species from 
Minnesota under the first of these three genera, which, as he remarks, 
may tje synonymous. From the Nuculid^ Mr. Ulrich has separated a 
number of species referred to the genus Lyrodesma and constitutes 
the family LvRODESMiDiE, taking L. planum Conrad, as a tyjje of the 
genus and adding two new species from Minnesota, viz: L. aeuminatuin 
and L. cannonense, besides his L. major {sic) for L. majus. The re- 
maining forms are referred to Technophorus, Miller; Allodesma, Ulrich 
(n. gen.); Rhytiinya, Ulrich; Cuneamya, Hall: Sphenolium, S. A. Miller, 
and Safifordia. 
Plates XXXV to xlii, inclusive, of this volume, contain no less than 396 
figures or illustrations of Lamellibranchiata. 
Chapter VII. The Loicer Silurian. Ostravoda of Minnesota. By E. 
O. Ulrich. The leading features in this interesting contribution to a 
humble though important group of fossil organic remains is the "pro- 
visional classification of the Pal;©ozoic Ostracoda," which at once gives 
us a very systematic and comprehensive view of the families and genera 
of North America, as well as foreign Ostracoda. Many of the recent 
changes in nomenclature made by Prof. T. Rupert Jones are adopted 
and a decided step in advance may be said to have been made as regards 
the study of these abundant little creatures of the old Palteozoic rocks 
of Minnesota. Such contributions to science by the State of Minnesota 
are a credit to the State and a help to palajontological enquiries the 
world over. The following genera are recorded from Minnesota: Lep- 
erditia, Leperdiiella, Schruidtella, Aparv.hites, Priinitiella, Primitia, 
Halliella, Beyrichia, Eiirycliilina, Dicranella, Jonesella, Bollia, Drep- 
anella, Di'obella, Ctenobolbina, Ceraiopsis, Tetradella, Moorea, Mac- 
ronotella, Cytherella, Bytliocypris and Kransella, comprising in all 
twenty-four species and varieties from the Lower Silurian of Minneso- 
ta. The four plates accompanying the letterpress contain 230 illustra- 
tions of Ostracoda, most of them magnified twenty diameters. 
{To be continued.) 
