l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 28 



vex and upsloping, about 0.8 times as wide as glabella ; palpebral lobes 

 not preserved. Surface of test granulated. Length of crandium 5 mm. 



Remarks. — Although this form is distinctive, it does not seem 

 proper to base a specific name on one cranidium. The closest described 

 species is Antagmus solitarius Lochman, which the writer would 

 rather include in Onchocephalus on account of the slight convergence 

 of the anterior facial sutures. The present form has shorter (sag.) 

 border and wider palpebral area. 



Occurrence. — Boulder M-io, Metis. 



Disposition oj material. — U.S.N.M. No. 123871. 



ONCHOCEPHALUS, species undetermined No. 2 

 Plate 3, figure 22 



Available material. — One perfect crandium. 



Description. — Glabella with slightly concave side outline, sharply 

 truncated in front ; four pairs of faint glabellar furrows visible. Oc- 

 cipital ring rather long (sag.), rounded in outline. Preglabellar field 

 very short (sag.) medially; border very prominent, convex; marginal 

 furrow of uniform curvature, lacking a median inbend. Palpebral 

 area slightly upsloping, 0.6 times as wide as glabella ; palpebral lobes 

 half as long as glabella, elevated ; distance from posterior end of 

 palpebral lobe to posterior margin less than length of palpebral lobe. 

 Posterior limbs with deep, straight furrow. Anterior facial sutures 

 parallel for the short distance between palpebral lobes and marginal 

 furrow ; posterior branch as in other species of genus. Surface of test 

 finely granulated. Length of cranidium 4 mm. 



Remarks. — This distinctive form differs from typical species of 

 Onchocephalus in the slightly upsloping rather than downsloping 

 palpebral area and somewhat longer palpebral lobes. The former 

 character brings it somewhat close to Periomma (e.g., cf. Periomma 

 gaspensis, pi. 4, fig. 15). As the only known cranidium is small, it 

 is possible that some of its features are due to immaturity. 



Occurrence. — Boulder G-41, Grosses Roches. 



Disposition of material. — U.S.N.M. No. 123872. 



ONCHOCEPHALUS, species undetermined No. 3 

 Plate 3, figure 21 



Available material. — One cranidium. 



Description. — Glabella straight-sided, moderately truncated in front, 

 sloping down to low anterior end; three pairs of glabellar furrows 

 fairly well impressed. Occipital ring long (sag.). Length (sag.) of 



