Benham. — On New Species of Earthworms. 279 



when contracted, lf^ in. (25*5 mm.). It appears to move 

 backwards' with almost the same ease with which it moves 

 forwards. 



But what is most remarkable is its ability to climb up a 

 vertical surface. I placed a specimen in a clean dry glass 

 beaker 4 in. in height. It climbed up this in a straight line, 

 and dropped over the edge on to the table. Here it remained 

 without a wriggle for a few seconds, in the same position as 

 it fell. I noted that it moved even more rapidly vertically up 

 this smooth glass than along the horizontal surface of the 

 table. On holding the beaker in various positions, it nearly 

 always took a vertical direction. 



The worm, when slightly pinched with forceps, readily 

 breaks into two pieces. It is not difficult to imagine the 

 value of these habits in the struggle for existence. The 

 negative geotaxis is, of course, of importance in gaining its 

 normal habitat. Its ready autotomy probably protects it if 

 perchance it is touched by a bird probing the log for grubs, &c. 



Anatomy. — The two species, P. sylvestris and P. lincatus, 

 agree closely with one another in external form and in 

 certain structural characters, and differ in some of these 

 respects from certain other species to be described below. 

 Each is about l^in. to 2 in. in length, and contains from 

 seventy to ninety segments. The body is relatively broad 

 in proportion to the length, and is broadest in the middle. 



The chcetce are about fifty in number, set in couples," of 

 which there are twelve or thirteen on each side. A distinct 

 dorsal and ventral gap exists, the width of which in rela- 

 tion to the ordinary gap between couples is variable, being 

 at least twice, or even thrice, the latter. 



In my note of 1898 I laid some stress on the differences 

 in the widths of these median gaps, but further comparison 

 leads me to consider such differences as individual or even 

 segmental variations. 



The elitcllum always covers segments 14 to 17, though 

 the number of fully mature individuals available does not 

 enable me to be certain as to any constant differences be- 

 tween the two species in this respect. 



The porophores on 17th and 19th segments are set in a 

 slight depression, capable of being converted into a narrow 

 furrow on contraction, so that the porophores meet their 

 fellows. This depression involves the ventral surface of 

 segments 16 to 20. The porophores are in line with the 

 lowest couple of chaetae ; the male pore, on the 18th, is just 

 outside this couple. There is no •spermatic groove, such as 



* As I have already stated (1898), Captain Hutton committed a 

 lapsus calami in attributing to P. lincatus a "continuous circle" of 

 chffitse. 



