new species of ocnerodrilus. 27 1 



Set^. 



But little mention has been made of the setae of the 

 different species. As species characters they are of 

 limited value, principally on account of the difficulty ex- 

 perienced in describing them properly, but also on ac- 

 count of the small variation between the different species. 

 In all the species the setae are sigmoid of the lumbricid 

 pattern, and in their general form there is but little or 

 any difference between those of various species. But 

 in size the difference is greater, as may be seen from 

 figures 74 to 82, where are represented the set^e of all the 

 varieties described by me. All the figures have been 

 drawn to the same scale (about 750 diameters) by means 

 of a camera, and are as exact as it was possible to make 

 them. The margins in all the forms are more or less 

 wavy, in some there is only a suggestion of undula- 

 tion, in others again the outlines are distinctly wavy. A 

 comparison of the figures will give a better idea than any 

 lengthy description. It will suffice to say that the an- 

 terior or free ends of the setae are more wavy than the 

 posterior parts. The setae of Ocnerodrihis Hendriei are 

 more wavy than those of any other species (fig. 77), and 

 are besides very characteristic in form. It is inter- 

 esting to note that the seta? of this species differ, both in 

 size, form and waviness, from the setae of O. guatemalce, 

 its most allied species. The setae of O. limicola are per- 

 haps the most characteristic of any, the general central 

 swelling here having given place to two rounded swellings 

 (fig. 78). 



With our knowledge, extended through the discovery 

 of new species, the following must be the diagnosis of the 

 genus: 



