A. REVIEW OF THE PROGRESS OF NORTH AMERICAN EST- 

 VERTEBRATE PALEONTOLOGY FOR 1884. 



By John Belknap Makcou. 



In this work I have endeavored to collect the titles of all of the works 

 on North American invertebrate palaeontology published during the 

 past year. An attempt has been made to give a brief idea of the con- 

 tents of each work, the new genera and species described, and the general 

 conclusions of the authors. The alphabetical arrangement by authors 

 seemed, after a good deal of thought, the best method of arrangement 

 and has consequently been adopted. The explanatory notices are placed 

 after each title. The work I hope will prove useful, and I will be glad 

 if those who notice them will call my attention to any omissions. 



Ami, H. M. — Notes on Triarthus spinosus Billings. (Trans. Ottawa 



Field Naturalists' Club, No. 4. Ottawa, 1883.) 



Interesting notes on this Trilobite with two figures, one a copy of 

 Billings's, the other original, with some of the furrows and grooves on 

 the occipital segment imperfectly figured. 



Beecher, C. E. — Ceratiocaridcc from the Chemung and Waverly Groups 

 at Warren, Pa. (Rep. of progress, P. P. P., 2d Geol. Surv. Penna., 

 pp. 1-22, pis. i and ii, Harrisburg, 1884.) 



A very interesting jmper on a group of which but little is known. 

 Gives descriptions of two new genera, Elymocaris and Tropidocaris, El. 

 siliqua n. sp. and T. hicarinata, T. interrupta, T. alternata n. sp., and 

 also a new species of Echinocaris, E. socialis n. sp. He also redescribes 

 and gives good figures of E. punctata Hall. The figures and descrip- 

 tions are excellent ; a short bibliography of the subject is also given. 



Billings, W. R. — Notes on, and description of, some fossils from the 

 Trenton Limestone. (Trans. Ottawa Field Naturalists' Club, No. 4. 

 Ottawa, 1883.) 



Describes a new species, Heteroerinus bellevillensi^, with good figures. 

 Gives a good illustration showing the arms of Dendrocrinus jewettii 

 B'llings, 1859 j he estimates their number at least at forty. Describes 



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