42 NORTH AMERICAN 



DIPLOGASTER, Max Schultz, 1857. 



Fig. 3, Plate II. 



35 



1.3 10.7 13.8 '51' 88.1 



3. Diplogaster fictor, Bastian 1.5 mm. 



1.3 1.4 1.4 1.7 1.4 



The thin layers of the transparent, colorless, practically naked cuticle 

 are traversed by exceedingly fine transverse striae, resolvable with high 

 powers under favorable conditions, which become considerably coarser to- 

 ward the head, where they are resolvable into rows of refractive dots ar- 

 ranged in longitudinal, as well as transverse lines. A short distance behind 

 the head the longitudinal rows arrange themselves in pairs. These pairs 

 indicate the locus of about twenty-four cuticular ribs or wings, which extend 

 from the middle of the neck to near the anus. On the tail these ribs again 

 resolve themselves into double rows of dots, and gradually disappear as the 

 tail grows narrower. Very little is to be seen of them behind the middle 

 of the tail. The cylindroid neck ends in a somewhat rounded head, which 

 bears near its outer margin a circlet of six somewhat forward-pointing, 

 tapering cephalic setae, each about one-third as long as the head is wide. 

 There is one of these setae on each submedian line and one on each lateral 

 line. Just in front of the base of each lateral seta a minute obscure pore or 

 papilla was observed, which did not appear to exist in connection with the 

 other setae. The amphids, though only faintly visible, are of relatively 

 large size. Their form is partly indicated by a lateral area on which the 

 punctations of the cuticle are absent. This is a somewhat elliptical area 

 placed transversely on the side of the head, with its long axis at right angles 

 to the lateral line. Its length is equal to half that of the correspond- 

 ing diameter of the head. Its anterior contour is more definite than the 

 posterior, although it is only by the most caerful focusing that the defintie 

 line of contour can be distinguished. Through the middle of the area, how- 

 ever, there is quite a distinct arcuate line, with its convex side toward the 

 lips. When seen dorso-ventrally the amphids have the appearance of 

 distinct oblique openings, leading inward and backward. When the mouth 

 is opened and the lips recurved the amphids are moved forward somewhat 

 and the transverse line mentioned becomes more strongly curved and forms 

 a semi-circumference. The circular mouth opening is very finely striated on 

 the inner surface of the lip region. These striae begin on the inner face of 

 the lips near where the cuticular wall of the pharynx first appears. They 

 extend backward nearly to the base of the pharynx and end in- 

 definitely. In front of this finely longitudinally striated area the transverse 

 marginal portion of the lips is more coarsely divided into fourteen 

 parts. The lips are capable of being opened, so that the oral aperture 

 is two-thirds as wide as the head. Under such circumstances it is seen 

 that the lip region is flower-like in form with fourteen recurved seg- 

 ments, the distal tapering portion of each of which is plain and 



