No. 2. — So7ne North American Fresh-Water Ithynchohdellidm, 

 and their Parasites.^ By W. E. Castll 



CONTENTS. 



I. Introduction 



II. Motliods 



III. Classification 



Key to Species 



IV. Description of Species . . . 



1. Glossiplionia stagnalis L. 

 a. Habitat, Form, Size, 



Color 



h. Rings, Somites, Eyes . 



c. Dorsal Gland, Suckers 



d. Reproductive Organs . 



e. Digestive Tract . . . 



/ Nepliridia 



g. Nervous System . . . 

 h. Metamerism .... 



(4) Number of Somites 

 o. Structure of a Typ- 

 ical Ganglion . . 

 j3. Fused Ganglia . . 



(2) Somite Limits . . 



2. Glossiplionia fusca, sp. nov 



a. Habitat, Form, Size, 



Color 



b. Rings, Somites, Eyes, 



Suckers .... 



c. Reproductive Organs 



d. Digestive Tract . . 



e. Nervous System . . 



3. Glossiplionia elongata, sp 



nov 



a. Habitat, Form, Size 



Color 



6. Rings, Somites, Eyes 



Suckers .... 



c. Reproductive Organs 



d. Digestive Tract . . 



PAGE 



18 

 18 

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21 



22 

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 26 

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 28 

 28 



29 



29 



31 



. 34 



34 



36 

 36 

 37 



38 



PAGE 



e. Nervous System ... 42 



4. Glossiphonia lieteroclita L. 42 



a. Habitat, Form, Size, 



Color 42 



b. Rings, Somites, Eyes, 



Suckers, etc. ... 43 



c. Reproductive Organs . 44 



d. Digestive Tract ... 45 



e. Nervous System ... 45 



5. Glossiphonia elegans Ver- 



rill 46 



a. Habitat, Size, Color . 46 



b. Surface, Rings, Somites, 



Eyes, Suckers ... 48 



c. Reproductive Organs . 49 



d. Digestive Tract ... 49 



e. Nephropores, Nervous 



System 50 



6. Glossiphonia parasitica 



Say 51 



a. Habitat, Form, Size 51 



h. Rings and Somites . 51 



c. Eyes, Mouth, Oral 



Sucker ..... 52 



d. Reproductive Organs . 53 



e. Digestive Tract ... 53 



f. Nephropores, Nervous 



System 54 



g. PapilliB, Coloration . . 54 



(1) Var. plana ... 54 



(2) Var. rugosa . . 55 

 V. Mutual Relationships of the 



Species Described .... 57 



VI. Parasites 59 



Bibliography 62 



Explanation of Plates 64 



^ Contributions from the ZoJdogical Laboratory of the Museum of Comparative 

 Zoology at Harvard College, E. L. Mark, Director, No. 112. 

 VOL x.xxvi. — No. 2. 



