Bull. U. S. F. C. 1899. (To face page 492.) 
Plate XII. 
132. Immature nematode (Ascaris) from Rhombus triacanthus. Head. 
X 225. 
133. Posterior end. • 225. 
134. Immature nematode (Ascaris) from Srlaowps occUatus. Head. 
X 225. 
135. Posterior end. x 50. 
135. Upper lip of older specimen from another lot. x 225. 
137. Posterior end. - 50. 
138. Ascaris sp. from Aland sapid issima. Head, ventral view. 200. 
Note. — T he specimens in this lot were somewhat distorted, 
the alcohol having evaporated from them. 
139. Another view of head of a different specimen from the fore- 
going. x 200. 
110. Ascaris vp. from Lobotcs siirinamensi*. Head, x 225. 
141. Upper lip. x 225. 
112. Post Tim end lateral view, x 225. 
! 143. iscarissp.; immature, from Raral ichth ijs dnitatus. Head, x 225. 
c y Embryonic cuticle; il, interlip; l , lip. 
111. Posterior end, lateral view, x 75. 
135. Extreme posterior tip. x 225. 
! 14G. Head of specimen from another lot, younger stage, x 225. 
