696 THE REPRODUCTIVE SYSTEM OF DIGASTER. 



EXPLANATION OF PLATES. 



Eeference letters. 



(i.r. Anterior rosette, a.s.r. Anterior median sperm reservoir, a.s.s. An- 

 terior sperm sac. a.t. Anterior testis, dit. Clitellum. f.o. Funnel of oviduct. 

 mc^. ix.-x. Mesentery between segments ix.-x. jiej)/;. Nephridium. o. Oviduct. 

 0.' Extra oviduct, ojy.o. Opening of oviduct, op.o.' Opening of extra 

 oviduct, ov. Ovary, p.r. Posterior rosette, p.s.r. Posterior sperm reservoir. 

 ;)..<;..<. Posterior sperm sac. p.t. Posterior testis, sp.' xp." sp.'" First, second 

 and third spermathecse. sp.g. Spermiducal glands, v.d. Yas deferens. 

 i-.d.ii. Point of union of the two vasa deferentia. r.H.f. Ventral nerve cord.. 



Plate liii. 



THfia^ter (Didymogaster) xijlvaticus. 



Fig. 1.— Dissection of the reproductive organs. The left halves of the 

 sperm reservoirs have been removed, exposing the testes and 

 ciliated rosettes of the left side. (x3). 



Plate liv. 



Ditjaster (Didymogaater) xylvaticu-^. 



Fig. 2. — Longitudinal section passing to one side of median line and 

 including segments ix.-xiv. ( x 13i). 



Fig. 3. — Longitudinal section showing presence of extra oviduct, o/ ( x 42). 



