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proximity to the lower part of XI/XII and with its long axis almost 

 parallel to the long axis of the body. The whole organ lies close to 

 the ventral body wall. It varies in shape within narrow limits, but 

 in general it resembles an elongated l)arrel. It also varies some- 

 what in dimensions, but the length averages about twice the diameter. 

 The anterior end has a well-differentiated collar which is set off from 

 the body of the organ by a constriction. Tliis collar varies in the 

 degree of the reflection of the margin, which is sometimes about 

 i8o° and sometimes only about 45°. The anterior opening is in close 

 proximity to the extremity of the testis. The sperm duct passes 

 through XI/XII very near to its union with the body wall. It is 

 long, much coiled, and confined to XII. 



Penial Bulb. — This organ (PI. VIII, Fig. 12) conforms to the 

 luiiibricillid type of penial bulb as defined by Eisen ('05, p. 8), and 

 does not differ markedly in structure from that of the other Ameri- 

 can species of this genus. It is small, and is not nearly so conspicu- 

 ous in transverse section as is usual in other Bnchytrccidcu. It is 

 covered by a definite musculature, a continuation of the circular muscle 

 layer of the body wall, which does not at any point penetrate into the 

 body of the bulb. The bulb is composed of two kinds of cells, 

 namely, those surrounding and opening into the penial lumen, and 

 those which fill the peripheral parts of the bulb, some of which appear 

 to open to the surface below the penial pore. The former are elon- 

 gated, nucleated, and stain very lightly, and are arranged radially 

 around the penial lumen. The peripheral cells are irregularly spindle- 

 shaped and .tend to take the stain heavily. The sperm duct pene- 

 trates the bulb near the ectal side and joins the penial lumen well 

 within the body of the bulb, \\nien the penial bulb is retracted the 

 penial lumen curves strongly towards the penial invagination, and the 

 penial pore is located well towards the base of the latter. 



Ovaries. — These organs occur as usual in XII, attached to the 

 ventral part of XI/XII. They are massive, filling a considerable part 

 of the coeloni in XII. The terminal part of each, which bears the 

 developing egg masses, is usually pushed up into the body cavity until 

 it lies dorsad to the digestive tract. 



Spcrmatheccc. — A single pair of these organs lies in V. The ectal 

 opening of each is laterad in the intersegmental groove IV/V and is 

 surrounded by a number of glands (PI. VIII, Fig. 7) which form a 

 sort of rosette. There is no marked differentiation of duct and am- 

 pulla. Within the ectal region, which is somewhat swollen, the lumen 

 attains its maximum diameter. This swollen region involves about one- 

 half of the entire spermatheca. The diameter decreases entad, the 



