22 



, .\I(VLI.L'8( AN C(^LL1:i:TI0N.S and l^KTKliMINATIONS. 



The .Station collections of mollusks, made mostly by Mr. Hart, con- 

 tain about 11,000 specimens, 600 of which are clams (Unionida^i. All this 

 material except that most recently brought in has been examined and deter- 

 mined by various American specialists. About eighty-five names of aquatic 

 or semi-aquatic mollusks have thus been obtained and their distribution and 

 life history have received special attention. The Unionidae have been studied 

 with reference to characters derived from the entire animal and much inter- 

 esting information has been accumulated concerning their relationships, life 

 histories, and parasites. 



FRESH WATER WORMS. 



The greater part of the time of Professor Smith available for State Labora- 

 tory work has been devoted to a study of the oligochaete worms (earthworms 

 and their allies) found in and about the Illinois River and other waters near 

 Havana. Most of this work has necessarily been of a systematic character, 

 although progress has been made along other lines. The importance of sj-s- 

 tematic work on this order is shown by the fact that with the exception of de- 

 scriptions of two species published in Vol. HI of the Bulletin of the State 

 Laboratory,* almost nothing has been known of the representatives of the 

 group in the Mississippi Valley and but little, indeed, for all the eastern pait 

 of the United States. 



Collections have been made from all the regular substations and at various 

 places in the bottom-lands and along the shores of the river to a point two 

 miles south of Havana. JNIany of the worms obtained were studied while liv- 

 ing, and for further study about seventy bottles of specimens have been pre- 

 pared and preserved in alcohol or formaline. For a successful study of most 

 of these worms serial sections are indispensable and thus far about four 

 hundred n^icroscopical slides of such sections have been made and used. 



The work of identification is now nearly completed and probably nearly all 

 of the diiferent species occurring in the region are represented on our lists. 

 Of the thirteen families of 01igt)ch£eta recognized by Beddard. nine are repre- 

 sented at Havana by thirty species belonging to sixteen genera. Less than 

 one half of these species occur in Europe and the remainder, with few excep- 

 tions, are known only from the United States. Two new genera and at least 

 seven new species have thus far been found by us. 



Numerous experiments have lieen made in rearing uaidiform worms and 

 considerable new information has thus been acquired concerning their asex- 

 ual reproduetion. 



Identification and description of the planarian worms of the Station collec- 

 tions has been kindlv undei'taken for us bv Professor W. M. Womiworth. of 



Art. IV. "On the Anatomy and Histology of a New Earthworm {DipJocardia rotnmunis''. 

 gen. et sp. nov.. by H. Garman; and Art. VII., "On an American Earthworm of the Family 

 Phreoryctidap," by S. A. Forbes. 



