ON AMPHILINA PARAGONOPORA 81 



EXPLANATION OF PLATES 3, 4, AND 5. 



N.B. — The magnifications given for all figiu'es are those at which the 

 figures were dra^vn. The extent to which these magnificatipns have been 

 reduced m ijrintmg can be estimated by comparison of the printed 5 cm. 

 scale with an actual 5 cm. The majority of figures were drawn under the 

 camera lucida. 



Plate 3. 

 Reference Letters in Figures 1-7. 



ANCC, giant anchor-cells ; bm, boring muscle ; CALC, calcareous bodies ; 

 DEC, dorsal external excretory channel ; dej, opening of ductus ejacula- 

 torius ; dnb, dorsal nerve branch ; dtc, dorsal transverse excretory 

 channel ; lec, lateral main excretory channel ; lel, lateral excretory 

 loop ; LLT, lateral longitudinal nerve trunk ; p, perforation at base of 

 left pectoral fin ; rtm, retractor muscle-fibres of proboscis ; ted, terminal 

 excretory duct ; tes, testes ; tr 1, u 2, u 3, first, second, and third limbs 

 of uterus ; vec, ventral external excretory channel ; vit, vitellaria ; 

 VNB, ventral nerve branch ; vop, opening of vagina ; vtc, ventral trans- 

 verse excretory channel. 



Fig. 1. — a, b, c, d, e, outlines of young specimens of Amphilina 

 paragonopora (drawn natural size); /, g, h, three specimens of A. 

 paragonopora showing transverse constrictions of body when removed 

 from the host ; j, an A. paragonopora which measured 280 mm. 

 when alive and uncontracted (contracted to 170 mm. when preserved). 

 The proboscis is evaginated ; k, the anterior end of the 280 mm. specimen 

 showing the evaginated proboscis as seen under the binocular ; I, the 

 posterior end of the same specimen showing the opening of the vagma 

 (dorsal) at the base of the papilla and the openiiig of the ductus at the 

 extremity. 



Fig. 2 (drawn natural size) illustrates some of the immobile, mostly 

 amorphous, masses which represent a phase in the life-history of the 

 species ; 2, a represents the young spherical and ovoid masses ; in 2, m, 

 one end of a large mass has assumed the form of the anterior extremity 

 of the active worm, and in 2, n, the posterior extremity of the active 

 worm is apparent. 



Fig. 3 (drawn natural size). — ^Anterior portion of a large A. para- 

 gonopora which has escaped from the body-cavity of the fish through 

 the perforation at the base of the left pectoral fin. 



Fig. 4 (xcir. 63). — Transverse section through A. i^aragonopora 

 about midway in the length of the body. 



Fig. 5 ( X cir. 63). — Sunilar transverse section at about the level of the 

 hind end of the anterior fifth of the body. 



NO. 265 G 



