[MATTHEW] STUDIES ON CAMBRIAN FAUNAS 123 



Plate VI. 

 (Btcheminian Fauna.) 



Fig. l.—Hyolithellus micans (pars), Billings.— a, two tubes parallel.— 6 and c, groups 

 of diverging tubes. All mag. f.— (?, tubes in association with those of Ortho- 

 theca bayonet. Nat. size. See p. 109. 



Fig. 2.—Coleoides typicalis, Wale. Portion of the tube. Mag. V- See p. 111. 



Fig. 3.—Orthotheca stiletto.— a, upper two-thirds of tube.— 6, outline of the aper- 

 ture. Both mag. -^. See p. 113. 



Fig. i.—Orfhotheca pugio.—a. Tube, distal half, ventral side.— 6, form of the 

 aperture.— c, transverse section in the middle.— fZ, side view of young tube. 

 —e, operculum supposed of this species. All mag. f. See p. 111. 



Fig. n.—Orthotheca sica.—a, distal part of tube, ventral side.— 6, outline of 

 aperture— c, a rounder variety, ventral side.— d, form of aperture.— e, an 

 operculum, perhaps of this species. All mag. ?. See p. 1 12. 



Fig. G.—Ofthothcca sica var. quadricostata.—a, distal part of tube, ventral side.— 

 h, form of the orifice. See p. 1 13. 



Fig. l.—Helenia granulata.—a, side view of the tube.— 6, view from above. 

 Both mag. f.—c, section of this tube, mag. f.— f/, portion of tube near aper- 

 ture, mag. l.—e, section of same, mag. ^. See p. 107. 



Plate VII. 



(Fig. 2 Mount Stephen Fauna, the rest Etcheminian). 



Fig. l.—Orthofheca bayonet.— a, tube showing the ventral side.— 6, tube, distal 

 part, dorsal side. Both nat. size.— c, young tube side view showing the 

 curve. — d, outline of the aperture. — e, transverse section of young tube. — 

 /, section of distal part of tube showing the apical angle.— c, d, e and /. 

 Mag. f. See. p. 114. 



Fig. 2.— Urotheca j)arva , n. sp. Chitinous tube with larval tube attached. Mag. f. 

 See p. 41. 



Fi^. 3.—Ryolithes excellens. Bill.— a, dorsal view.— &, side view.— c, form of aper- 

 ture. — d, section in the equidorsatal part of the tube.— e, operculum. — 

 /, same in profile. All nat. size.— g, side view of young operculum.— A, oper- 

 culum of young or of another species. — i, same in profile. The three last 

 mag. y. Seep. 115, 



Fig. 4. — Hyolithes rugosus.—a, tube showing dorsal side. — b, side view of tube. 

 Both mag. f. See p. 118, 



Fig. 5.—AptycJiopsis terranovicus. Side view of right valve. Mag. {. See p. 118. 



Fig. Q.—A. terranovicus, mut. arcuata. Mag. f. See p. 119. 



Plate VIII. 

 (Protolenus Fauna). 



Fig. l.—Metadoxides magnificus. Matt.— «, restoration from parts. The head and 

 thorax from actual examples ; the thorax restored.— 6, a ring of the thorax 

 showing the .sculpture and broken axial spine.— c, a pleura showing the 

 surface markings of the under side.— rZ, a smaller pleura from the inside.— e 

 a portion of the genal spine to show the diagonal raised lines. All nat. size. 

 See p. 89. 



