336 abstracts: zoology 



Mixed crystals or isomorphous mixtures varying in composition from 

 that of pure potassium ammonothallite to that of a product represented 

 by the formula TINK2 . 4NH3 . 3 . 6KNH2 have been obtained from 

 liquid ammonia solutions of potassium ammonothallite containing an 

 excess of potassium amide. E. C. F. 



PALEONTOLOGY.— Ca?n6nan Brachiopoda. Charles D. Walcott. 

 Monographs of the U. S. Geological Survey 51. Part I, text, pp. 

 872; Part II, pis. 104, pp. 363. 1912. 



This monograph describes 44 genera, 15 subgenera, 477 species, and 

 59 varieties of Cambrian Brachiopoda, and 3 genera, 1 subgenus, 42 

 species, and 1 variety of Ordovician Brachiopoda. Of the Cambrian 

 forms, 10 genera, 2 subgenera, 21 species, and 1 variety persist into the 

 Ordovician. 



In this paper the Brachiopoda are treated in three ways — ^historically, 

 geologically, and zoologically. Historically the treatment comprises (1) 

 a bibliography and (2) a table of synonymic reference, giving a com- 

 pletely cross-referenced list of described species with the present generic 

 and specific reference of each. Geologically the distribution of the 

 Brachiopoda is considered under the following headings: (1) General 

 geographic and stratigraphic distribution; (2) detailed geographic dis- 

 tribution; (3) detailed stratigraphic distribution; (4) habitat; and (5) 

 fossil localities. Zoologically the discussion covers (1) the physical char- 

 acters of the Brachiopoda; (2) their distribution; (3) their evolution; 

 and (4) their classification. Lastly come the detailed descriptions of 

 genera and species and the illustrative plates. P. V. Roundy. 



ZOOLOGY. — On a collection of recent Crinoids from the waters about 

 Ireland. Austin H. Clark. Department of Agriculture and Tech- 

 nical Instruction for Ireland, Fisheries Branch; Scientific Investiga- 

 tions, 1912, no. IV, pp. 1-5. 1913. 

 The collection upon which this report is based was brought together 

 by the Irish fishery cruiser Helga while working in the seas to the west 

 and north of Ireland; the description of a single specimen taken in the 

 Faeroe Channel by Dr. Wolfenden's yacht Silver Belle is also included. 

 Though small, the collection is of very considerable interest because 

 four of the eight species represented are new to the coasts of the British 

 Islands, one of these representing a genus heretofore known, in the 

 Atlantic basin, only from the Caribbean Sea. 



The eight species are: Antedon petasus (Dtiben and Koren) (not 



