1892.] AN ABNORMAL EARTHWORM. 1«5 



of the somites. The anterior pair (fig. 1, ov.^) was borne upon the 

 mesentery separating the 11th and 12th somites, and immediately 

 dorsal to the coiled portion of the vas deferens which emerges from 

 the latter segment. This pair is slightly the largest. 



The 2ud pair {ov.^) is situated on the 13th somite, and has all the 

 typical relations of the ovaries as found in the uormal worm ; facing 

 them, and piercing the mesentery 13/14, we find a small pair of ovi- 

 ducts (ovd.) with well developed receptacula ovorum (r.o.). Side by 

 side with the latter structures, on the 14th somite, is a 3rd pair (ov.^) 

 of these conical white bodies, slightly smaller than those in front, but 

 resembling them in position and structure. On the 15th somite is 

 situated the 4th pair (ov.^), the members being smaller, of unequal size, 

 and no longer exhibiting the free tapering apex so characteristic of 

 the anterior ones. The 5tli, 6th, and 7th pairs of these bodies (ov.\ 

 ov.'', and ov.') lie respectiA^ely on the 16th, l/th, and 18th somites, and 

 show a marked decrease in size ; they are relatively rounder and less 

 regularly developed, the members of each pair being often unequal 

 in size ; further, those on the 17th somite are slightly larger than the 

 corresponding ones on the 16th. 



A rough examination with a hand-lens while the worm was still 

 fresh showed that the free ends of these structures were composed of 

 a number of large rounded cells, which at once suggested ova, 

 especially as the pair of these bodies on the 13th somite possessed all 

 the relations of the typical ovaries of the normal worm. 



The specimen was subsequently clarified in glycerine, and subjected 

 to a microscopic examination, which entirely confirmed the last ob- 

 servation. Each of these bodies consisted of a number of rounded 

 cells, smaller at the broad end, and becoming larger and rounder at 

 the free end, the tapering apex being composed of a single row of 

 these large cells (Plate XIU., ov.^-oo.^, o.), in each of which can be 

 seen a large round nucleus and one or two nucleoli. 



A comparison with the ovaries of a typical worm shows that the 

 anterior pairs of these structures can in no way be distinguished from 

 them, either in structure, position on their segments, or in shape. 

 The four posterior pairs (fig. 2, ov.^-ov.'), however, rather resemble 

 the ovaries of a very young or immature worm, being rounder and 

 smaller, composed of smaller cells, and only showing one or two 

 large round cells so characteristic of the adult ovary, while they are 

 entirely destitute of that very characteristic free filamentous termi- 

 nation composed of ripe ova. 



From the consideration of the above description, together with a 

 comparison of the figures given, there can be no doubt that each 

 pair of these 7 cell-masses is the serial homologue of the single 

 pair of ovaries of the normal Earthworm ; so that this interesting 

 specimen, instead of possessing only a single pair situated on the 

 13th somite, is rich in the possession of seven pairs of ovaries, 

 situated respectively on segments 12 to 18 inclusive. 



The condition and shape of the three anterior pairs suggests that 

 they have already been functional in the discharge of ova into the 

 body-cavity ; while the four posterior pairs are in a more rudimentary 



