DESCRIPTIONS OF GENERA AND SPECIES 327 



(4) Pachydrilus pagenstecheri, Ratzel. 

 Enehytraeus pagenstecheri, Ratzel, Z. Wiss. Zool. 1868, p. 587. 

 Pachydrilus pagenstecheri, Vejdovsky, Ench. 1877, p. 53. 

 P Enehytraeus pagenstecheri, Taubek, Ann. Dan. p. 7 a. 

 Pachydrilus limosus, Dieffenbach, An. Syst.-Stud. 1885, p. 106. 

 Definition. Length, 1^-2,0 mm.; number of segments, 55-60; setae, 3-5 in dorsal, 7-10 in 

 ventral bundles. Brain concave in front. Spermathecae with distinct duct twice the length 

 of pouch, beset with glands. Hah. — Germany ; Bohemia. 

 This species is easily to be distinguished on account of the numbers of the setae 

 differing in the dorsal and in the ventral bundles. Ude never found more than 

 six setae in the ventral bundles, which appears to upset the above distinction. Pachy- 

 drilus limosus of Dieffenbach, which Ude identifies vrith P. pagenstecheri, has not 

 more than five setae in a bundle. I am not at all sure that P. limosus is not a good 

 species. 



(5) Pachydrilus subterraneus, Vejdovskt. 

 Pachydrilus subterraneus, Vejdovsky, Rev. Biol. Nord, Vol. I. No. 4, p. i. 

 Definition. Length, 20 mm. ; number of segments, 50-55 ; setae, 5-8 per bundle ; prostomium, 

 buccal segment, and half of the following covered with papillae. Spermathecae without 

 distinction between pouch and duct, funnel of sperm-duct unusually long. Hah. — Prague ; 

 Lille; underground waters. 

 This species has been investigated by Vejdovsky and is well characterized. It has 

 the outward appearance of a Tubifex or a Phreatothrix, and the blood-vessels of the 

 anterior part of the body, not specially described by Vejdovsky, are very long and 

 coiled, contributing largely to this resemblance. A curious local peculiarity dis- 

 tinguishes the specimens from Lille ; they have a circle of glandular cells surrounding 

 the aperture of the spermatheca which are wanting in the individuals found in Prague ; 

 the sperm-duct funnel is extremely long reminding one of the same organ in Marionia 

 ebudensis ; it is represented by Vejdovsky as slightly coiled. 



(6) Pachydrilus maximus, Miohaelsen. 

 Pachydrilus maximus, Miohaelsen, JB. Wiss. Anst. Hamb. 1888, p. 56. 

 Definition. Length, 40 mm. ; number of setae per bundle tip to 7. Brain convex in front ; out- 

 growths of nerve-chord completely cover chord laterally. Spermatheca with a short but 

 distinct duct, surrounded at its extremity with a mass of glands. Hab. — South Georgia. 

 This species is the largest, not only in the genus Pachydrilus, but among the 



