PLATE XXVII * 
Fig. 30. Gracilisentis gracilisentis from intestine of Dorosoma cepedianum. 
Optical section of fully mature male. Whole mount in balsam, stained in 
hematoxylin. 
Fig. 31. Surface view of proboscis of gravid female of same species, showing 
types of hooks and their arrangement. Paracarmine-stained whole-mount in 
balsam. 
Fig. 32. Embryo from body cavity of gravid female of same species. 
Fig. 33. Tanaorhamphus longirostris from intestine of Dorosoma cepedi- 
anum. Optical view of fully matured male. Hematoxylin-stained specimen in 
balsam. 
Fig. 34. Embryo from body-cavity of gravid female of same species. 
Fig. 35. Hooks from surface of proboscis of gravid female of same species, 
showing difference in size and form characteristic of different regions: (a) pro- 
file of eighth hook from base of proboscis in one of the longitudinal rows upon 
the ventral surface; (b) fifth hook from the base in a row upon the lateral 
surface of proboscis; (c) fourth hook from base of proboscis in a longitudinal 
row upon the ventral surface. ’ 
* Scales indicating magnification of Fig. 30 and 33 have a value of 1 mm.; all 
others in the plate have a value of 0.05 mm. 
