TREMATODES FROM EISHES — LINTON 27 



GASTEROSTOMUM CAPITATUM, new species 



Plate 18, Figures 236-239 



Fusiform, tapering rather more toward anterior than posterior 

 end; densely covered with minute, blunt spines; anterior sucker 

 ventral, preceded by a capitate hoodlike structure, which when fully 

 expanded is much broader than the diameter of the neck at the level 

 of the anterior sucker, Vitellaria 16 or more on each side, separated 

 from the anterior sucker by a space equal to one-fifth or more of the 

 length and extending little, if any, back of the level of the ventral 

 sucker. Ventral sucker a little in front of the middle of the body; 

 intestinal caecum, in uncompressed specimens, posterior to ventral 

 sucker; ovary on right side of intestine; testes on right side, close 

 together, one following the other, the first testis near the ovary. The 

 cirrus pouch extends forward to the level of the second testis. The 

 uterus may fill the greater part of the body back of the vitellaria, but 

 was not observed to extend in front of the vitellaria. 



Type specimens. — U.S.N.M. No. 8172 (holotype and paratypes). 



Table (3. — 3Ieasurements of five specimens of Gasterstomum capitatum in balsam 



Measurement 



Length... 



Breadth, of capitate head 



Breadth, level of anterior sucker. 

 Breadth, near middle, maximum 



Anterior sucker, length.. 



Anterior sucker, breadth.. 



Diameter ventral sucker 



Anterior end to vitellaria 



Anterior end to ventral sucker... 



Mm. 

 1.05 

 .21 

 .15 

 .42 

 .12 

 .12 

 .07 

 .35 

 .52 



Host. — Frigate mackerel {Auxis rochei) . 



Record of collection. — Seventeen (U.S.N.M. No. 8172), collected 

 July 12, 1912. Dimensions, life, compressed: Length, 2.21 mm.; 

 breadth, of capitate anterior end, 0.24 mm., maximum of body, 0.66 

 mm.; diameter of anterior sucker, 0.21 mm., of ventral sucker, 0.1 

 mm. ; ova, 0.015 by 0.01 mm., shells not thick. 



