ni'io African Earthworm. 453 



Internal Anatomy. 



Ill tlic arrangement of the internal oigaus of this species 

 there is litile that ealls for special notice. It agrees closely 

 in almost all points with that nsnal in the genus. 



S(jine of the anterior septa are wanting, as in other 

 species ; judging from the external segmentation, the missing 

 ones are vi./vii.-viii./ix. The se[)ta anterior to vi./vii. are 

 represented only by muscle-strands connecting the alimentary 

 canal with the body-wall. The first true septum, recog- 

 nizal)le as such, is apparently ix./x. This absence of septa 

 makes it ditficult to decide to which segments the gizzards 

 and other organs belong. Tiie septa ix./x. and x./xi. are 

 pushed back considerably by the second gizzard, and both 

 join the alimentaiy canal close t(jgether behind it. The two 

 gizzards are not very distinct externally, but the separate 

 muscular thickenings of their walls are easily seen on cutting 

 them open. 



There are three pairs of calciferous glands, situated, as 

 usual, in xv.-xvii. The last pair is the largest, and the first 

 the smallest. The glands of the first pair are sometimes of 

 a much whiter appearance than the others, probably owing 

 to the much greater quantity of calcareous crystals contained 

 in them. The ducts of the glands open separately into the 

 alimentary canal. 



There is a single dorsal blood-vessel. The last pair of 

 hearts is situated in segment xii. 



Concerning the excretory system it is advisable to speak 

 witli some reserve. It is probable, however, that, with 

 noaterial specially preserved for histological investigation, the 

 nephridia of this species would prove highly interesting. 

 For the present it will be sufficient to indicate their peculiar 

 arrangement. In the anterior half or two-thirds of the 

 body there is in each segment, midway between the septa 

 Avhich limit it before and behind, a slight transverse mesen- 

 tery, which seems to run completely round the inside of the 

 body-wall, save for its interruj)tion in the mid-ventral line 

 by the nerve-cord and a slight gap on the dorsal side. On 

 either side of this mesentery there is a series of small, 

 whitish, flattened lobes, each of which may be regarded either 

 as a separate nephridial organ or as a branch of a large 

 compound ne})hridium. Tlieie is a tult of such lobes, 

 smaller than the re5>t, near the mid-ventral line on either 

 side. These lobes are connected with a narrow duet wliich 

 runs, in the thickness of the mesentery, round the segment. 



