XVII. STUDIES ON THE ANATOMY OF INDIAN 

 MOLLUSCA. 



2. THE MARSUPIUM AND GLOCHIDIUM OF SOME UNIONIDAE 

 AND ON THE INDIAN SPECIES HITHERTO ASSIGNED TO 

 THE GENUS NODULAR! A. 



By B. Prashad, D.Sc, Superintendent of Fisheries, Beyigal, Bihar and 

 Orissa, Calcidta. {Communicated by permission of the Director of 

 Fisheries, Bengal.) 



(With text-figures 1-3.) 



In part one^ of this series I described the structure of the marsupium 

 and the glochidium of two species of the genus Physunio, Simpson. 

 Tlie present communication consists of two parts, the first of which 

 deals with the same structures in two of the common genera of Indian 

 Unionidae Lamellidens, Simpson, and Parreyssia, Conrad, while in the 

 second an account of the soft parts of the animal of an Indian genus 

 hitherto confounded with the genus Nodularia, Conrad, is given. A 

 new generic name, Indonaia is, therefore, proposed for the Indian species. 

 An account of the structure of the glochidium of two of the species of 

 this genus is also included. Further, a few records of the occurrence of 

 encysted glochidia on the fins of some Indian fishes are given. 



A full histological account of the structure of the gills in these genera 

 is not included as I hope to come to this subject later and to deal with the 

 Indian Unionidae as a whole. 



The material for this investigation consists of a collection made by 

 Babu D. N, Sen, Zoological Assistant, Bengal Fisheries Department, 

 and the various collections made on different occasions by the officers 

 of the Zoological Survey of India ; these latter collections were very 

 kindly placed at my disposal by the Director of the Zoological Survey of 

 India. 



I have also to express my indebtedness to Mr. T. Southwell, the 

 Director of Fisheries, for the kind encouragement and the generous 

 way in which he has met with my wishes at all times. To Babu D. N. 

 Sen my thanks are due for the careful records of locality, preservation 

 of specimens and wiUing help whilst working with me in the Fisheries 

 Laboratory. 



General. 



The marsupium is of very great importance in the classification 

 and natural grouping of the genera of the Unionidae, but unfor- 

 tunately at the time of Simpson's- revision the anatomy of the 

 Indian genera was not known in most cases. He, however, from a 



^ Rec. Ind. 3Ius. XV, p. 1S3-1S5, pi. xxii (lOlS). 

 ? Proc. U. S. Nat. Mus. XXIT, p. 501-107r> (1!)(H)). 



