136 Transactions. — Zoology. 



undergo their development in egg-sacs, which occupy segments 

 xiv. to xvi. (about). 



" 15. The spermathecas are present to the number of from 

 two to three pairs in segments vii., viii. (and ix.)." 



Genus Pelodeilus, Beddard. 



Pelodrilus violaceus, Beddard. Trans. Boy. Soc. Edin., 

 vol. xxxvi., Part 11 (No. 11). 



This interesting species occurs in the rich mould on the 

 edge of an old swamp, the property of A. Curtis, Esq., of 

 Tinwald, near Ashburton. In habits, as well as in structure, 

 it occupies an intermediate stage between aquatic and terres- 

 trial worms. When its minute burrows are examined with a 

 lens they are seen to be thickly coated with a semi-transparent 

 fluid. Its very minute cocoons are deposited, like those of 

 the higher forms, outside the walls of the burrows, and occa- 

 sionally almost flush with them. Like those of the preceding 

 species, they are pear-shaped, and are unlike the oblong-shaped 

 cocoons of several strictly terrestrial species. The following is 

 Beddard's anatomical description of this Annelid : — 



"The length of the specimens varies from lin. to 2in.; 

 they are very slender, and resemble a Plireoryctes or Lumbri- 

 culus. Most of them have the clitellum well developed; and 

 this fixes the period of maturity to the month of August, when 

 they were collected. 



''External Characters.- — -(1.) The prostomium of Pelodrihis 

 is short and blunt, and very inconspicuous in the preserved 

 specimens ; it has no resemblance to that of Plireoryctes, 

 which is divided by a furrow into two portions. (2.) The seta 

 exist upon all the segments of the body except the first. They 

 are arranged in four couples, both of which are, in the anterior 

 part of the body at any rate, rather lateral in position. I 

 could detect no difference of size between the seta? of the 

 more dorsal and of the more ventral couples, such as I have 

 shown to occur in Plireoryctes. The shape of the setaa is in no 

 way distinctive ; they agree with those of Phrcoryctes, the 

 Lumbriculidce, and most earthworms. (3.) Clitellum : In 

 Pelodrilus the clitellum occupies segments xi.-xiii. It is 

 only developed on the dorsal side of the body. In the region 

 of the clitellum the body is much swollen, owing to the 

 tension caused by the genital products. So far, therefore, as 

 can be said at present, Pelodrilus comes nearer to Plireoryctes 

 than to the Lumbriculida. (4.) Ncphridio'pores : These are 

 situated in front of the ventral pair of setae. 



"Integument. — The most interesting fact relating to the 

 structure of the body-wall in Pelodrilus is its great thickness 

 in the anterior, as compared with the posterior, segments. 



