44 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



shaped and sac-like with open ends of C to left, lower arm of C 

 directed anteriorly (fig. 13), approximately length and diameter of 

 lower horizontal arm of ovary. Genitointestinal canal present. Vitel- 

 laria separated anteriorly extending from genital pore to middle of 

 posterior haptor where they unite. Two vitelline ducts unite in mid- 

 line about one third distance from genital pore to ovary forming 

 common yolk duct which extends straight posteriorly turning to 

 right at lower end before joining oviduct. No mature egg present. 



Comparisons. D. caulolatili is most like D. neoviaenis. In both 

 species the posterior pair of suckers is smaller than the anterior pairs. 

 D. neomaenis is larger (9.0 mm. in length as compared to 4.5 to 4.9 

 mm.) and has twenty-five testes and twelve cirrus hooks, whereas 

 D. caulolatili has fifty-six to sixty-five testes and thirteen cirrus 

 hooks. 



D. caulolatili is named after the genus of the host, Caulolatilus. 



Heterobothrium ecuadori, new species 



(Plate 5, figs. 16-19) 



Host: Cheilichthys aimulatus (Jenyns) 

 Location: Gills 



Locality: Tagus Cove, Albemarle Island, Galapagos Is- 

 lands, San Francisco, Ecuador 

 Number: 4 



Body lanceolate, thin, flat, and left side with pronounced greater 

 curvature, 2.903 to 3.466 mm. in length by 0.866 to 1.256 mm. in 

 greatest width, three times as long as wide. Posterior haptor not 

 separated from body proper, approximately one fourth total body 

 length, 0.763 to 1.017 mm. in length by 0.915 to 1.213 mm. in 

 greatest width. Four pairs of posterior suckers arranged in the 

 shape of a horseshoe, four on each side with open end of horseshoe 

 pointing anteriorly, elliptical, slightly broader than long, 0.152 to 

 0.203 mm. in length by 0.186 to 0.271 mm. in width. Chitinous 

 skeleton (fig. 19) consists of two lateral pieces on each side and a 

 central piece with short, T-shaped distal end. Mouth slightly sub- 

 terminal leading into large mouth cavity. Anterior mouth suckers 

 large, elliptical, longer than wide, 0.169 to 0.220 mm. in length by 

 0.118 to 0.186 mm. in width. Pharynx large, elliptical, slightly wider 

 than long, 0.084 to 0.118 mm. in length to 0.085 to 0.120 mm. in 

 width. Esophagus very short without lateral branches. Intestinal 



