364 W. BLAXLAND BENHAM. 



The worm is rather flattened, and the posterior end, which 

 is lighter in colour, tapers off to a point, apparently in the 

 same sort of way as in M. robustus, A. G. B., for which 

 species I at first took it; but in that species the gizzard differs 

 in extent and position. 



The prostomium is rounded, not embedded in the peristo- 

 mium at all, but is retracted in the same sort of way as Bed- 

 dard (5) found in his species. 



The somites are separated by deep intersegmental grooves ; 

 the first and second, as Beddard points out in his last contri- 

 bution (6) to the anatomy of M. Barwelli, are very short, 

 the two together barely reaching the length of the third 

 somite. 



The chsetae are of the normal shape (fig. 2), and do not 

 agree with those figured by Horst for M. Houtenii, nor 

 with those figured by Beddard (5) ; they are small, as in the 

 other species, measuring 2 mm.; the free end is rather more 

 hooked than in M. Barwelli. All four couples of chsetae in 

 the present species are on the ventral surface, so that none are 

 visible from above. Thsir arrangement, as I have inferred 

 above, is of some specific importance. In all species of 

 Moniligaster the individuals of each couple are very close 

 together, and the space between the two ventral couples — i. e. 

 the ventral space — may be equal to, greater than, or less than 

 the lateral space or distance between the dorsal and ventral 

 couples of either side (see fig. 1). 



Thus in M. japonicus, Mich., M. Beddardii, Rosa, the 

 ventral space (V) = the lateral space (L); in M. Barwelli, 

 M. uniquus, A. G. B., V < L ; in M. grandis, A. G. B., 

 as in the present species, V > L; whilst in M. Houtenii 

 V = 2L. 



In the remainder of Bourne's species no reference is made 

 to this point. 



The nephridiopores appear to commence in Somite vi, 

 but on dissection I find nephridia anterior to this. 



I failed to discover any dorsal pores, either by means of a 

 lens or by mounting a piece of the body-wall in Canada 



