'rkcMMDOLEPTirS FaUXA AT CaNANDAUU'A LaKK, X. \'. SI 



Perfect specimens of the little Ostracods of the genera //(t/Z/ZcAz and 

 Kirkhya, whose shells are merely a fine network, were obtained, and also 

 many of the Rhombopora-like Bryozoa covered with minute spinules. 



The jielecypods, which are nearly all inmiature individuals, are 

 excellently preserved, and many of them retain the prodissoconch. 



The advantage of this method of collecting is shown in the great 

 number of specimens of supposedly rare species obtained. Pholidops 

 hamiltonice, which is rare in ordinary collections, is extremely abundant 

 in this material, only one species being more common. Pholidops 

 ohlata, of which not more than a dozen specimens have been obtained 

 from other localities, has been obtained by the hundreds. Ascodictyon 

 stellatitDi, Aiitodetiis lindstrcoiii, and the Ostracods, which are rarely 

 found in any quantities, are here very common. 



The whole fauna consists of about 115 species so far identified and 

 10 or 12 species whose specific identity is uncertain, some of them 

 probably new. The fauna is distributed as follows, Crustacea : Trilo- 

 bita, 5 species; Ostracoda, 11 species; Cephalopoda, i species; 

 Gastropoda, 8 species ; Pteropoda, 3 species ; Pelecypoda, 16 species ; 

 Brachiopoda, 38 species ; Bryozoa, iS species ; Vermes, 6 species ; 

 Anthozoa, 5 species. 



A large proportion of the individuals of the Brachiopoda are in im- 

 mature stages, many of them being less than one millimeter in length 

 and there are specimens showing all gradations in size up to the adult, 

 and in many cases, to the senile conditions. Series showing all these 

 stages were picked out whenever possible, and carefully studied to 

 ascertain what changes took j)lace during the lives of the individuals 

 of the various species. 



The ])ioneer work of this sort was done by Beecher and Clarke on 

 material obtained from Waldron, Indiana. In the memoir which 

 they published giving the result of this work, the development of 25 

 species, belonging to 18 genera, was described. Later work by 

 Beecher, Schuchert, and Cumings has added a full description of 

 several more. Among the fossil Brachiopoda, two genera of the 

 Rhynchoneilidce, three of the Atrypidi\2, two of the Spiriferid;e, three 

 of the Athyrids, one of the Cranidoe, one of the Kichwaldidc\2, four 

 of the Strophomenidre, four of the Orthida;, and one of the Poram- 

 bonitid?e, have been studied in this way up to the present time. 



In the present paper the full series of changes are described for 

 twenty other species and notes are made on four more. In this 



