234 W. B. BENHAM. 



mid-line, or both. Setse usually small aud of equal size, aud 

 generally equidistant, though in some species more or fewer 

 of the more ventral ones are larger than the rest. On the 

 clitellum the setee are invisible. 



Clitellum on Somites xiv to xvi or xvii, rarely only two 

 or more than four ; well defined, and altogether obliterating 

 the intersegmental grooves. 



Spermiducal pores in Somite xviii, usually rather later- 

 ally placed. 



Oviducal pores in Somite xiv very close together, or more 

 usually single and median. 



Penial setse and various " copulatory papillse" are fre- 

 quently present. 



Sperm-sacs, in Somites xi and xii, two pairs, rarely more, 

 and sometimes connected by median sacs enclosing testes. 



Prostates. — A pair in Somite xviii, lobed or greatly sub- 

 divided, or even digitate; the duct after being joined by the 

 sperm-duct is very muscular and probably protrusible ; it 

 may be called a " penial duct." 



[Worm cylindrical ; prostomium sometimes dovetailed into 

 peristomium, sometimes not dovetailed. 



Dorsal pores present. 



Testes and ciliated rosettes in Somites x and xi, sometimes, 

 at any rate, enclosed in the median portion of the sperm-sac. 



Ovaries in Somite xiii. 



Spermathecse, usually only two pairs, in Somites viii and ix, 

 opening anteriorly ; sometimes only one pair ; sometimes more 

 than two pairs. Usually with an appendix which varies in shape. 



Gizzard occupies any position between Somites v and x. : 

 usually occupying three Somites, viii, ix, and x. 



In most species a pair of tubular caeca in Somite xxvi are 

 present.] 



Species 1. P. houlleti, E. P., 1872; Calcutta (and Nice); 

 Bahamas (F. E. B.) ; Manila (F. E. B.). 

 2. P. post hum a, Vaillant, 1869 = P. affinis, 

 E. P., 1872 ; Cochin China ; Java (liorst) ; 

 Philippines (F. E. B.). 



