No. 5 meserve: monogenetic trematodes 63 



Pseudaxine mexicana, new species 

 (Plate 9, figs. 60-63) 



Host: Scomberomortis maculatus (Mitchill) 

 Location: Gills 



Locality: Tangola-Tangola, Mexico 

 Number: 2 



Body relatively short and narrow curving to left, 1.950 mm. in 

 length by 0.322 to 0.373 mm. in width at widest part at middle of 

 body and tapering slightly anteriorly and posteriorly. Posterior hap- 

 tor almost as wide as length of body proper, extremely convex at 

 posterior end, bearing thirty-seven suckers. Posterior suckers large, 

 elliptical, broader than long, 0.058 mm. in length by 0.088 mm. in 

 width. Chitinous skeleton (fig. 61) of suckers has broad triangular 

 piece at anterior of central piece which has two lateral hook-like 

 prolongations at distal end; middle part of central piece double with 

 wide elliptical opening between the two sides, joining at posterior 

 to form another triangular piece which is not quite as wide as an- 

 terior one; two pairs of relatively slender curved pieces at sides, 

 one pair somewhat longer than the other and after enlarging at 

 distal tips tapering to fine points; one pair imbedded in base of 

 sucker almost touching each other medianly, approximately one 

 third width of sucker, wider at proximal end, extending obliquely 

 anteriorly and laterally; six to seven slender, equidistant pieces im- 

 bedded in each side of sucker. Mouth subterminal, ventral. Pharynx 

 bulb-shaped, 0.044 to 0.056 mm. in length by 0.028 mm. in width. 

 Esophagus relatively short and slender, bifurcating in region of 

 genital pore. Intestinal limbs with lateral branches, not united be- 

 hind. Genital pore well forward one half distance from anterior end 

 to anterior border of vitellaria. Testes from posterior to ovary to 

 haptor, relatively small, wider than long, irregularly arranged in 

 two rows, thirty-six in number. Vas deferens a relatively wide tor- 

 tuous tube winding horizontally twelve to fourteen times before 

 reaching upper end of ovary where it is more slender and passes 

 almost straight posteriorly in mid-line to testes, enlarged at anterior 

 end to form cirrus. Cirrus armed with ten straight, slender pointed 

 spines pointing anteriorly, arranged around top of cirrus in a circle 

 and slanting inward toward each other at the anterior end; 0.018 

 mm. in length. Ovary slightly posterior to middle of body on left 



