332 OLIGOCHAETA 



but not described), have a very short anteseptal part ; the duct arises some little 

 way behind the septum. 



(4) Marionia crassa (CLAPAEtDE). 



Pachydrilus crassus, CLAPAEfeDE, M^m. Soc. Phys. Gen., 1862, p. 79. 

 M. crassa, Michaelsen, Abh. Nat. Ver. Hamb., 1889, p. 29. 



Definition. Length, i^mm.; number of segments, 48; setae, 2-5 per bundle. Spermathecae 



furnished at base with minute glands. Lymph corpuscles of two different hinds. Kab. — 



Island of Shye. 



It seems to me to be a little doubtful whether this species is really referable to 



the genus Marionia or to Pachydrilus. The sharp demarcation of two kinds of lymph 



corpuscles is not met with elsewhere in the genus, and is used by Michaelsen to 



distinguish the species from other Marionia. Some of the cells are roundish with 



numerous granules, the others have the form more usual in the genus and are fusiform 



with no granules. Another point in which the species differs from other members 



of this genus or the last is in the form of the ' testes.' Clapabede describes them 



as extending from the eighth (ninth) to the eleventh (twelfth) segment, an extent 



which is suggestive rather of sperm-sacs than testes. The fact that the organs in 



question are unpaired ^ is in favour of this suggestion. I do not pretend to speak 



decisively upon the matter, which requires looking into. 



(5) Marionia georgiaiia, Michaelsen. 



Pachydrilus georgianus, Michaelsen, JB. Hamb. Wiss. Anst., 1888, p. 65. 

 M. georgiana, Michaelsen, Abh. Nat. Ver. Hamb., 1889, p. 29. 



Definition. Length, 8 mm.; setae, 5-7 j»e?- bundle. Spermathecae with few glands at pore. 

 Dorsal vessel springs from a cup-like depression upon intestine. Hob. — South Georgia. 



The last character in the definition distinguishes the species. The duct of the 

 spermatheca is about half the length of the pouch. Septal glands are developed in 

 segments iv, v, vi. The dorsal vessel originates at end of thirteenth segment. 



' Clapae^de uses the singular in writing of them. But so does he in the species M.fusca, so that this is 

 perhaps not quite enough reason for inferring that the organs are unpaired, d'Udekem, however, describes 

 as 'unique,' and figures as single, the ovary oi Fridericia gcdba. 



