344 Record.'^ of ihe Indian Mvseum. [Vol. XV, 



Literature cited — 



1. Gaylord, H. R. and Marsh, M. C. — Carcinoma of the Thyroid 



in the Salmonoid fishes. Institute for the 

 study of Malignant diseases. Serial No. 

 99. Washington, 1914. 



2. Southwell, T. — Notes from Bengal Fisheries Laboratory. 



Indian Museum, No. 2. On some Indian 

 parasites of fish with a note on Carcinoma in 

 Trout. Rec. Ind. Mus., Vol. XI, Part IV, 

 No. 16, August, Calcutta, 1915. 



II. ON SOME INDIAN MYXOSPORIDIA. 

 Plate XI. 



Except for a short note on a species of Myxoholus by one of us (9) 

 practically nothing is known about the Indian Myxosporidia, Whilst 

 working out the collections made by the Bengal Fisheries Department 

 during the last few months we found three new species of the genus 

 Myxoholus, Biitschli. Two of the species are unicapsulate forms, whilst 

 the third is bicapsulate. A short note on another Myxosporidian of the 

 genus Sfhaerosfora, Thelohan, in the collection of the Zoological Survey 

 of India, is also included here. 



Myxobolus rohitae, sp. nov. 



This interesting parasite was found infesting the gills of Laheo rohita 

 (Ham. Buch.). The fishes in question were caught in the Turag river 

 at Mirpur, district Dacca, on the 2nd of June, 1917. A second lot of 

 specimens was obtained on the 22nd of January, 1918. Unfortunately 

 no observations were made on the living material, but well preserved 

 specimens of the gills have enabled us to make a fairly complete study 

 of the parasite. The infection was of a very heavy nature, involving 

 all the gills of the fish in question, and, as will be seen from fig. 1, the 

 cysts were scattered all over the surface of each of the gills. In one 

 case 53 such cysts were counted on one surface of a single gill. The 

 infection was equally severe over the rest of the gills of both the right and 

 left sides. 



Serial sections of the cyst, 3 to 4 fji thick, were cut by the ordinary 

 paraffin method, and stained with Giemsa's solution, or Heidenhain's 

 iron haematoxylin, followed by eosin. Besides sections, cysts were 

 dissected and the spores thus removed were examined unstained, and 

 also stained with Giemsa's solution. The sections of the cysts were 

 found to be quite satisfactory and showed all the necessary stages. 



The cyst (fig. 1). — The cysts preserved in spirit are of a creamy- 

 yellow colour, measuring 3"1- — ^3*8 mm. long and 0*8 — 1*2 mm. broad. 

 They lie with the long axis of the cyst parallel to the gill-filaments. 

 The cyst varies in shape from oval to cylindrical. The ends are rounded 

 while the surface attached to the gill-filaments is flattened. The 

 infected gill-filaments were in no way specially enlarged or different 

 from the other gill-filaments. 



