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PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 101 



31 (30 



32 (33 



33 (32 



34 (35 



Oral spines not over 48; eggs not over Sb/x 32 



Suckers subequal; oral spines interinipted ventrally megacephalum 



Acetabulum larger than oral sucker; oral spines not interrupted 



ventrally . 34 



Numerous vitelline follicles between ovary and anterior 



testis ditrematis 



No or very few vitelline follicles between ovary and anterior testis 36 



Cirrus sac not reaching halfway to ovary; oral spines 36 sentum 



Cirrus sac reaching halfway or more to ovary; oral spines not 36 38 



Sucker ratio about 1:2; oral spines 38 to 40 anisotremi 



Sucker ratio about 1:1.26; oral spines 33 to 34 imparispine 



Vitellaria extending some distance along cirrus sac but not 



reaching acetabulum 41 



Length not over 1.9 mm.; eggs about 47^ long minutum 



Length much over 1.9 mm.; eggs at least 60fi long 43 



Acetabulum about twice size of oral sucker bicoronatum 



Acetabulum considerably less than twice size of oral sucker 45 



Oral spines 40 to 42 46 



Numerous vitellaria between ovary and anterior testis hispidum 



Few or no vitellaria between ovary and anterior testis tenue^ 



Oral spines 30 to 36 49 



Cirrus sac extending considerably more than halfway 



to ovary cloacum 



Cirrus sac extending only halfway or less to ovary 51 



Cirrus sac S-shaped, wider in anterior half coryphaenae 



Cirrus sac almost straight; wider in posterior half 53 



Eggs 94 to 109/u. long californicum 



Eggs SO/ji long cesticillum 



STEPHANOSTOMUM CALIFORNICUM, new species 



Plate 13, Figure 13 



Description (based on the single specimen collected). — Length 

 4.786 mm., greatest width 0.482 mm., near posterior end. Oral 

 sucker 0.219 mm., acetabulum 0.321 mm. in transverse diameters; 

 sucker ratio approximately 1:1.47. Oral spines 33, although a 

 space at the middorsal line suggests that a thirty-fourth spine had 

 been lost ; spines in anterior row 80 to 90/x long ; spines in posterior 

 row 61 to 78/A long. Forebody length 1.255 mm. or slightly less 

 than one-fourth body length ; posttesticular distance 0.606 mm. or 

 approximately one-half length of forebody. Prepharynx 0.547 

 mm. long; pharynx pyriform, 0.292 mm. long by 0.255 mm. wide; 

 esophagus very short; intestinal bifurcation a short distance 

 preacetabular ; ceca extending close to posterior end of body, prob- 

 ably opening into excretory vesicle. 



* Linton (1940) has reported S. tenue from six hosts at Woods Hole, but his figures 32 and 34, 

 with very different extent of the cirrus sac, suggest that he may have dealt with more than one 

 species. Martin (1939) has described the life cycle of this species. 



