40 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



Entobdella muelleri, new species 

 (Plate 4, fig. 9) 



Host: Cratinus agassizii Stelndachner* 



Location: Gills 



Locality: Tagus Cove, Albemarle Island, Galapagos 



Islands 

 Number: 1 



Body elongated oval, more than twice as long as wide, 4.116 mm. 

 long by 1.603 mm. in greatest width. Posterior haptor circular and 

 unlobed, 1.083 mm. in diameter with narrow marginal membrane. 

 Anterior pair of hooks 0.176 mm. in length, straight, relatively 

 strong. Middle pair of hooks large and powerful, 0.50 mm. in length, 

 arcuate with recurved points. Posterior pair of hooks 0.100 mm. in 

 length, straight, with short, fine recurved points. Larval hooks 0.020 

 mm. in length. Anterior pseudosuckers 0.508 mm. in length, ellipti- 

 cal, slightly broader than long with thin, flat crenate margins. Oral 

 sucker weakly five-lobed, slightly broader than long, 0.440 mm. in 

 width. Pharynx present and can be seen in ventral view through 

 mouth opening as two kidney-shaped muscular structures close to- 

 gether with concave sides toward each other. Esophagus probably 

 present but not visible. Intestinal limbs with lateral branches, not 

 united posteriorly. Testes approximately in mid-body, side by side 

 and close together, smooth, unlobed, slightly longer than broad, 

 small, 0.339 mm. in length by 0.235 mm. in width, each pierced by 

 nine dorso-ventral muscles. Glands of Goto 0.080 mm. in length by 

 0.048 mm. in width, elliptical, longer than broad, tipped obliquely 

 toward each other anteriorly and located a relatively great distance 

 posterior to testes. Cirrus sac bulbous, approximately twice as long 

 as wide, just posterior to left of oral sucker, not quite one third of 

 distance from oral sucker to ovary. Genital pore to left of oral sucker 

 opposite mouth approximately two thirds distance from posterior 

 to anterior border of oral sucker. Ovary elliptical, smooth, broader 

 than long, relatively far anterior to testes, 0.305 mm. in length by 

 0.339 mm. in width, smaller than testes. Seminal receptacle intra- 

 ovarian. Vitellaria extend from anterior suckers to posterior end of 

 animal. Yolk reservoir anterior to ovary, three times as long as 

 broad, its width approximately equal to width of ovary, slightly 



* For the identification of this host the writer is indebted to Dr. G. S. Myers 

 of the United States National Museum. 



