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



indefinite nodulus about one-third of the length from the free end. The forking is 

 always very fine, and is practically never visible without the employment of an 

 immersion lens {cf. text-fig. 2 : plate xvi, figs. 10 and 11, represent my earlier 

 views as to these setae, the one (fig. 10) representing the usual and the other (fig. 11) 

 what I at first considered the " abnormal," i e., bifid, variety). 



What is perhaps the most typical constitution of a dorsal bundle is the presence 

 of one long and one short seta. But the bundle may be constituted by two hair- 

 with one needle-seta, or one hair- with two needle-setae, or two of each, or one 

 needle-seta alone. It occasionally happens that no dorsal setae of any kind are visible 

 on a segment which ought normally to bear them. When it is remembered that the 

 hair-setse themselves may or may not have the thorn-like processes described 

 above, may be of various lengths, and may or may not be broken short, it will be 

 seen that the dorsal setal bundles may vary in different cases very widely indeed ; 

 in one and the same animal almost every bundle may present differences as compared 

 with every other. 



Two varieties of setal sacs are shown in figs. 12 and 13 ; it will be seen that one 

 is lobulated and massive, the other attenuated. The lobulated form is apparently 

 the rarer. 



The body-cavity contains many lymph-corpuscles ; these are of two kinds, white 

 and brown. The white (fig. 12) contain a large number of bright refractile spherical 

 granules, usually indeed appearing to be made up of them. The brown ones contain 

 a number of minute particles which appear to be droplets of a brown oily substance ; 

 they resemble those described later for Pristina. An animal may have only white 

 corpuscles, or may have both white and brown ; never, so far as I have seen, brown 

 only. I did not observe any brown corpuscles till May; it is possible that their 

 presence is seasonal, and perhaps determined by the more plentiful food supply at 

 the beginning of the hot weather ; the brown particles appear to be of the same 

 nature as those in the wall of the alimentary canal. I could not correlate the 

 presence of the brown corpuscles with any other structural peculiarity. 



The septa are well-marked ; there are also strands connecting alimentary canal 

 and body- wall. 



Alimentary tract. — The buccal cavity occupies the second segment. The pharynx 

 occupies the third, fourth and fifth {v. plate xv, figs, i and 2) ; it is mobile, but not 

 protrusible. Surrounding the pharynx on all sides are a number of ovoid or pear-shaped 

 hyaline nucleated cells, the masses of which give to the pharynx a somewhat nodular 

 appearance. Occasionally a portion of this cellular mass is somewhat detached from 

 the pharyngeal tube ; in plate xvi, fig. 14, is shown such a mass, partially detached 

 from the dorsal wall of the pharynx, th- alimentary tube itself being ventrally situated, 

 and possessing apparently no specially thickened muscular walls {cf. the description of 

 the pharynx and septal glands of Pristina^ post.). The oesophagus occupies the sixth 

 and part of the seventh segments ; it contains in its wall numbers of minute 

 brownish particles looking like oil droplets. A dilatation, more or less defined, in the 

 seventh and eighth segments, may be called the stomach ; this portion of the tract 



