NOTES ON THE NAIDIFORM OLIGOCHJITA. 353 



It is very small, about 8 mm. long. 



The majority of my specimens in which there were no genera- 

 tive organs, and which were not budding, consisted of eighteen 

 to twenty-one segments. 



I frequently found the ventral setse of the fourth segment in 

 non-budding individuals to be much larger and stouter than 

 the other ventral setee. These were probably modified genital 

 setse, but I never obtained specimens showing any further 

 sexual developments. The dorsal setse are all capillary and of 

 similar lengths throughout the body. There are usually two in 

 the bundle, one longer than the other ; but those of the third 

 segment are not extra long, as is the case in P. longiseta. 



The " stomach " lies in segment viii. 



The blood is yellowish. 



I observed a single pair only, of commissural vessels. 



The most anterior nephridia lie in segment ix, and not in 

 segment x, as in P. longiseta. 



The coelomic corpuscles are very large, and greenish in colour. 



I observed numerous budding individuals, but in all cases 

 there was only a single budding region in any particular speci- 

 men, from which I infer (though not with certainty) that as 

 soon as a chain of two zooids is formed a separation takes 

 place. 



The budding takes place after segment xiii (i.e. w = 13), 

 and there are seven segments in the new head (i.e. z' consists 

 of seven segments). The most anterior of these becomes the 

 peristomial segment, and the remaining six develop dorsal and 

 ventral setse; so that in the adult they are indistinguishable, so 

 far as the setse are concerned, from those which follow. 



3. P. breviseta, sp. n. (PI. XXVII, figs. 11—15). 



This is a species which I found in enormous numbers in one 

 or two localities in Madras ; and although I hope to describe it 

 and other Indian Naids in detail at some future date, I refer 

 to it now because, from observations made upon it, J have been 

 enabled to verify the law of budding described in the foregoing 

 portion of these notes. 



