60 Illinois State Laboratory of Natural Historij. 



first, but rapidly increases in diameter, and passes outwards 

 and upwards along the inside of the body-wall. Outside the 

 outer pair of setiB the tube is abruptly bent and returns upon 

 its course until within the outer setyo; then turns outwards 

 again and extends about half as far as in the first loop; returns 

 again upon its course; and finally, as a slender tube, passes 

 down within the mesentery which holds the gland to the 

 body-wall, and reaches the latter in front of the dorsal seta of 

 the outer pair. In specimens prepared according to Seraper's 

 "dry method," the nephridiopores show very clearly at the 

 anterior edge of each somite, in line with the outer setae. 

 There seem to be no pores in somites 1 and 2. 



All the specimens of Diplocardia thus far examined have 

 shown the external apertures of the vasa deferentia on somite 

 19, and hence behind the clitellus. If we follow M. Per- 

 rier's classification rigidly, we must, therefore, place this genus 

 in the group ])ost-cUteMiani. The position of the male pores 

 so near the posterior limits of the gland would seem to indi- 

 cate an intermediate position for the genus, and other features 

 of its anatomy apparently confirm this impression by pointing 

 to relations with genera in both the divisions intra-axidi post- 

 clitelliani. Thus, of the fourteen characters of the genus 

 Microchaeta, one of the intra-cUtelliani, given by Mr. W. B. 

 Benham,* five (2, 4, 6, 10, and 14) are, in essentials, common to 

 the two genera, while as many more points of likeness could 

 be selected which as clearly indicate a relation of the genera. 

 M. Perrier's genus Anteus, another of the intra-clitelliani, also 

 bears some resemblance to Diplocardia. In both, the nephridio- 

 pores are in a line with the dorsal seta of the outer pair; the 

 anterior septa are thick and muscular; the setje are disposed in 

 four double, longitudinal rows, and the gizzard is anterior in 

 position. Recognizing M. Perrier's divisions as good, we may 

 consider these resemblances to indicate an inferior position for 

 our genus. The lower forms of a group often combine in 

 themselves characters distributed in a number of higher forms, 

 and this we may suppose to be the case with Diplocardia. At 



* Quart. Jour. Micr. Sci., X. Ser., No. CII., 1886, p. 201. 



