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NEW NORTH AMERICAN EARTHWORMS 159 



various organs in Oligochaeta and not infrequently in those used at 

 different times by the same writer. In describing the reproductive 

 organs the writer prefers the terms spermaries and ovaries, respec- 

 tively, for the male and female gonads and also the terms sperm 

 ducts and oviducts for the ducts through which the germ cells pass 

 on their way outward. The terms sperm sacs and ovisacs are used 

 for the chambers that are formed by evagination of septa of the 

 gonad somites and that provide space in which the germ cells may 

 pass through a part of their development. The term spermathecae is 

 used for the chambers having openings on the outer surface of the 

 body wall and that store the sperm cells received from some other 

 individual. The term prostates is used for certain organs associated 

 with the male reproductive organs of some kinds of earthworms, in- 

 cluding those described in this paper. The terms spermathecal ducts 

 and prostate ducts are applied to the ducts through which the cavi- 

 ties of the spermathecae and prostates, respectively, are in communi- 

 cation with the exterior. 



The openings of the various ducts at the body surface are termed 

 pores, and there are spermiducal pores, oviducal pores, spermathecal 

 pores, and prostatic pores. Because of the fact that in some kinds 

 of earthworms, including those described in this paper, the sperm 

 ducts open into the cavities of the prostate glands or ducts instead 

 of at the body surface, thereby making but one pair of surface pores 

 for these two or three pairs of organs, there is chance for confusion 

 if either of the terms spermiducal pores or prostatic pores is used 

 in the description of such species. The term male pores seems to the 

 writer to be preferable and is used in the descriptions herein for 

 openings that are outlets for both prostate ducts and sperm ducts 

 that have united before reaching the surface. 



In some groups of earthworms, including many of the Megasco- 

 lecidae, there is present a longitudinal blood vessel in close relation 

 with the median dorsal surface of the alimentary tract of a few of 

 the somites of the posterior half of the esophagus and lying between 

 it and the dorsal vessel. The term supraintestinal is commonly used 

 for this vessel, even though it is connected with the esophagus in- 

 stead of the intestine. Another term sometimes used is supra-eso- 

 phageal, which seems preferable and is used in the descriptions herein. 



The term "hearts" is often applied to certain contractile com- 

 missural vessels connecting the dorsal and ventral vessels. In some 

 kinds of earthworms some of these hearts have their dorsal connec- 

 tion with only the dorsal vessel and are called dorsal hearts, while 

 some of the posterior ones may have connections with both the dorsal 

 and supra-esophageal vessels and are termed dorso-esophageal hearts. 

 In the species of Merfascolkles here described the supra-esophageal 

 vessel is not so definitely separated from the dorsal part of the vascu- 



