272 Memoirs of the Indian Museum. [Voi,. I, 



the third segment, the œsophagus occupying segments iv-viii, and the globular 

 stomach in segment viii. The animal has been mutilated at its posterior end. 



Text-fig. 5 shows what is, I think, a specimen of P. œquiseta, the prostomium 



^ 



Pig. 5. — Sketch of a specimen of Pristina œquiseta with abnormally short prostomium. 



exhibiting no elongation at all. It will be seen that the dorsal setae begin in the 

 second segment and are of equal length in all segments ; septal glands are present in 

 segments iii- vi, and a globular stomach in segment viii; and to my original sketch 

 notes are appended to the effect that the dorsal bundles contained constantly one 

 long and one short seta, that the ventral bundles contained three setae, and that the 

 first nephridium occurred in the ninth segment. In all these points, the specimen 

 agrees with the form just described as P. cequiseta. It is curious that this animal, 

 like the last, should also have been mutilated at its posterior end. A second 

 specimen of P. œquise'a was also met with, showing a prostomium but little larger 

 than that of text-fig. 5, and much shorter than that of the normal animal. 



These variations are interesting as bearing on the morphological value of the 

 length of the prostomium. Beddard [2] is of opinion that it is slight, and would group 

 together under one name genera which differ in little else than the length of the 

 prostomium. It would, in fact, appear from the above specimens that an amount 

 of variation supposed to characterize different genera may occur within the limits 

 of a single species. 



Slavina punj ahensis , sp. nov. (PI. xix, fig. 41.) 



This worm was found in considerable numbers in two ponds in the Lawrence 

 Gardens, lyahore, during the months of April and May, 1907; and again in April, 

 1908. In length it varies considerably ; the average length appears to be about 

 6 mm., but specimens up to 12 or 15 mm. have been met with. Like the species 

 of Pristina previously described, it moves backwards apparently with as great 

 freedom as forwards. 



As seen with the naked eye, its colour is whitish and somewhat opaque ; under 

 the microscope, the animal is seen to be covered with foreign particles, diatoms and 

 grains of inorganic matter, which may be so thickly spread as to obscure almost 

 completely the internal anatomy ; these foreign particles may be more thinly 

 distributed posteriorly, where the animal is then consequently more transparent. 

 In such cases (fig. 42), there may be seen a homogeneous colourless or slightly yellow 



