14 Dr. P. Miiller on Lumbricus corethrurus. 



a tolerably uniform tbickness posteriorly. The number of seg- 

 ments is about 200-250, of which 13 are in front of the clitellus ; 

 the latter, which is often wanting, includes 8 segments. The 

 foremost segment is grooved longitudinally, like the three anterior 

 segments in Geoscolcx maximus, Leuck. When the animal, feel- 

 ing about, extends che head, one or two similar segments, together 

 with a clavate head-lobe with a long peduncle, make their ap- 

 pearance from the first segment. On the foremost segments the 

 bristles exhibit the usual position, the four bristles of each side 

 being approximated in pairs ; the upper pair is continued as far 

 as the clitellus, whilst the two bristles of the lower pair gradually 

 become more distant ; from the clitellus backwards we see on each 

 side only two rows of separate bristles : these are the first and 

 third rows counting from below upwards; the latter runs about 

 the middle, between the belly and the back ; the insertion of 

 the second and fourth bristles varies in height on each segment, 

 but without any definite law being perceptible ; sometimes, for 

 example, they are placed alternately higher and lower, so that 

 those of the 1st, 3rd and 5th, and again those of the 2nd, 4th 

 and 6th segments lie in the same longitudinal line ; sometimes 

 three are elevated and two again depressed, so that those on the 

 1st and 5th segments stand at an equal height, those on the 2nd 

 and 4th higher, and those on the 3rd still higher ; sometimes also 

 they maintain the same height on several consecutive segments, 

 &c. After a greater or less number of segments (<?.^. 20-30), 

 the two rows of bristles still existing also cease their regularity : 

 first the lower row, and then the upper one which runs along 

 the middle of the side ; these bristles also then vary in the height 

 of their insertion from segment to segment. This apparently 

 perfectly chaotic arrangement of the bristles becomes regular 

 again in the vicinity of the hinder margin, by each segment 

 bearing 8 bristles standing nearly at an equal distance apart, 

 which alternate with those of the contiguous segments, by which 

 16 longitudinal rows (or also 3 sph-al lines) of bristles are pro- 

 duced. It is remarkable that this singular arrangement of the 

 bristles does not occur in young animals ; these have two rows 

 of pairs of bristles at the anterior extremity, which further back 

 separate into four rows of isolated bristles. 



The bristles on the anterior part of the body are more delicate, 

 and appear to be slightly hooked ; those on the hindermost part 

 are very strong, straight and amber-coloured, stand upon distinct 

 tubercles, and appear to be incapable of being entirely retracted. 

 From these 16 rows of strong bristles, the whole tail acquires 

 a brush-like appearance. The stomach is strongly muscular. 

 The egg-capsules are almost globular, colourless and opalescent j 

 I never found more than one embryo in them. 



