242 W. N. F. WOODLAND 



secondarily simplified. The evidence of Looss^ to the effect 

 that a cercaria stage occurs in the life-history of Sanguinicola 

 requires confirmation before a decision can be arrived at, 

 and if it be confirmed, it will be of interest to know how the 

 naked eggs liberated into the blood of the fish are transported 

 to the intermediate Molluscan host. 



DESCEIPTION OF PLATE 18. 



o^, male aperture. $, female aperture (vaginal pore). ' dg ', ' dotter- 

 gang '. EE, narrow opening from fertilization chamber into vagina. 

 EGG, ripe eggs. GS, gut sac. M, mouth. NC, nerve commissure, oe, oeso- 

 phagus, ooo, narrow opening of oviduct into fertilization chamber. 

 OTP, fertilization chamber. ' otp ', hypothetical ootype. ov, ovary. 

 OVD, oviduct. OVDB, dilated oviduct, ovdn, narrow portion of oviduct. 

 PEN, penis. PH, pharynx, pmus, muscle-cells surrounding pharynx. 

 SOL, solid posterior extremity of body behind dorsal furrow, sp, spinelets. 

 TEP, terminal excretory pore, tes, testes. ' UT ', ' uterus '. vag, vagma. 

 ' VAG ', ' vagina '. vagb, dilated part of vagina, vagn, narrow part of 

 vagina, vagp, vaginal pore ($). vagr, vaginal groove on surface, vd, vas 

 deferens, vr, dorsal body furrow, v-v, w-w, x-x, y-y, z-z, planes of 

 sections across fig. 7 corresponding approximately to the figures of actual 

 sections in figs. 7, v, w, x, y, z. 



Fig. 1 ( X cir. 87). — Sanguinicola viewed from the ventral aspect. 



Fig. 2 ( X 180). — Transverse section across Sanguinicola behind the gut sac 

 (the convex surface is ventral). 



Fig. 3 ( X 39). — Sanguinicola in dorsal surface view. 



Fig. 4 a ( X cir. 120).— Unusually small contracted pharynx. 



Fig. 4:, h, c, d {x cir. 120). — The undistended (6) and distended (c, d) 

 pharynx in three Sanguinicola. 



Fig. 5 ( X 530). — The undistended pharynx. 



Fig. 6 ( X 530). — The gut sac and opening of oesophagus. 



Fig. 7 ( X 260). — The posterior genital ducts and openings from the 

 ventral aspect, v-v, w-w, x-x, y-y, z-z represent approximately the 

 planes of the sections shown in fig. 7, v-z ( x 180). 



Fig. 8 ( X 530). — The posterior genital ducts and apertures magnified 

 to show the character of the walls of the former. 



Fig. 9 ( X 840). — The spinelets embedded in the edge of the dorsal body 

 furrow. 



Fig. 10 ( X 840). — Eggs contained in the fertilization chamber. 



Fig. 11. — Diagram to show the genital ducts as figured and described 

 by Dr. Plehn in her second paper (1908), for comparison with fig. 1. 



^ Quoted by Odhner. 



