PLATE I. 



Figure 1. — Pliiloscia vittata Say (p. 306); dorsal view, enlarged six diameters; 

 natural size indicated by cross at the right. 



2. — Scyijhacella arenicola Smith (ji. 307) ; dorsal view, enlarged about twelve 

 diameters; natural size indicated by cross at the right. 



3. — Actoniscus ellipticus Harger (p. 309) ; dorsal view, enlarged ten diame- 

 ters ; natural size indicated by line at the right. 



4. — Jffira albifrons Leach (p. 315); female; dorsal view, enlarged about ten 

 diameters. 



5. — The same ; maxilliped from the left side, exterior view, enlarged twenty- 

 five diameters ; P, palpus ; I, external lamella. 



(■). — The same; maxillse, enlarged twenty-five diameters; a, outer, or second, 

 pair of maxillae ; b, inner, or first, pair of maxillse ; i, inner, e, outer 

 lobe. 



7. — The same ; inferior surface of the pleon of a female. 



8. — The same ; inferior surface of the pleon of a male. 

 (All the figures were drawn from nature by O. Harger.) 



