No. 5 meserve: monogenetic trematodes 41 



constricted in middle. Vagina not seen. No mature egg present in 

 type specimen. 



Comparisons. E. muelleri differs from E. hippoglossi in possess- 

 ing no papillae in posterior haptor. It differs from E. soleae in having 

 no papillae on the body. It is more similar to E. steingroveri but its 

 posterior hooks are different. The posterior hooks of E. steingroveri 

 are split almost their whole length. The posterior hooks of E. muelleri 

 are not split. E. muelleri has glands of Goto which are absent in E. 

 steingroveri and differs from E. convoluta which has no glands of 

 Goto, possesses an anterior adhesive hood connecting the pseudo- 

 suckers and an extremely long cirrus pouch. 



Since there is only one specimen, the type, the species is pro- 

 visional. 



E. muelleri is named after Mueller, who named the type species 

 of the genus. 



Encotyllabe pagrosomi MacCallum, 1917 

 (Plate 5, figs. 10-12) 



Host: Caulolatilus sp. 



Location: Gills 



Locality: James Island, Galapagos Islands 



Number: 1 



The following species of Encotyllabe Diesing, 1850 have been 

 described to date: E. nordmanni Dies., 1850, E. pagelli van Ben. and 

 Hesse, 1863, E. pagrosomi MacCal., 1917, E. paronae Mont., 1907, 

 E. spari Yamaguti, 1934, E. vallei Mont., 1907 and E. lintoni Monti- 

 celli, 1909. 



Only one specimen was collected for which reason it is provision- 

 ally identified as E. pagrosomi. Price (1937) has redescribed E. 

 pagrosomi and the comparisons made in this paper are based on his 

 redescription. 



MacCallum's four specimens were from the "mouth and throat" 

 of Pagrosomus aurattis (Houttuyn). Price (1937) gives the follow- 

 ing measurements for MacCallum's material: 5.0 to 5.4 mm, in 

 length; 1.4 mm. in width. The specimen of the author is 2.166 mm. 

 in length by 1.266 mm. at its greatest width. Its large hooks measure 

 0.254 mm. as compared to 0.360 to 0.380 mm. The width of the 

 large hooks is 0.080 mm. which is one half the length of MacCal- 



