162 MATTHEW ON CAMBRIAN 



Fig. 13. — Lcperditia Sleadi, u. sp.— 13a, Right valve, natural siiie.— 13((, Longitudinal section. — 13c, Transverse 

 section. From Band 6', St. John Group. See p. 1 60. 



Pl.\te VIII. 



Fig. 1. — Oholus pulchcr, n. sp., (dorsal valve). 1«, Embryonic shell seen from above. Mag. 'j'. — 1//, Same, view of tlie 

 hinge area. — Ic, Same, seen from the side. — \d, Another embryonic shell with deeper previsceral 

 depression. Mag. '^. — le, Same in section. — 1/, Larval shell, inner half shaded. Mag. {. — \g, Adolescent 

 shell, inner half shaded (with larval and embryonic shell included.) Mag. '{ — l/i. Adult shell showing 

 all the stages and the outline of the visceral cavity. Mag. ; — li. Interior of dorsal valve showing the 

 median and lateral ridges, and the muscular scars. Mag. ;. — \h, Another example less perfectly 

 preserved, shortened by pressure. INIag. ;. — 1?, Mould of the dorsal valve showing the muscular scars 

 and tlie internal layers of the shell partly broken away. Mag. j. — \m, Another mould narrowed by 

 pressure, with the internal layers more completely removed, and showing the vascular lines more 

 distinctly. Natural size. All from Band fc'-', Caton's Island. See p. 151 . 



Fig. 2. Oholus pulehcr, n. sp., (ventral valve).— 2a, Embryonic shell seen from above. Mag. V. — 26, Same, showing 

 the hinge line. — 2c, Same seen from the side. — 2d, Complete larval shell (with embryonic shell in outline). 

 Mag. {. — 2e, Complete adolescent shell (with embryonic and larval shell included). INIag. ;. 2/, Adult 

 shell showing all the stages of growth and the outline of the visceral cavity. — 2g, View of the hinge in 

 the larval stage showing a tube (?) and foramen. Mag. j. — 2h, Interior of the ventral valve, showing the 

 place of the pedicle, the vascular groves and the scars left by tho muscles. Mag. f. — 2t, Ventral Valve 

 partly decorticated, revealing the outline of the ventral cavity. Mag.f. — 2^-, Mould of the ventral valve 

 laterally compressed, showing points of attachment of the pedicel, the foramen, the vascular strife and 

 scars left by the muscles. Mag. f. — 21, Another mould showing variations in the internal markings. 

 Mag. ;. All from Band 6 '"', Caton's Island. See p. 151. 



Fig. 3. — Obohis major, n. sp., Interior of dorsal valve. Natural size. From Div. 2h, Basal series, Hanford Brook. 



See p. 155. 

 Fig. 4. — Lhujuhlhi Martinensis, n. sp., Interior of ventral valve. Natural size. From Band lb, \ St. John Group. 



Hanford Brook. See p. 155. 

 Fig. 5. — Volborthella tenuis, Schmidt. — 5o, Large example.- 5b, Smaller specimen showing the septa. Both mag. f. 



From Band ft, St. John group, Belyea's Landing.— 5o, Example, with shell replaced by hematite. — 



5rf, Same in section to show siphuncle (?) Both mag. j. From Div. 2b, Basal series. Hanford Brook. 



See p. 156. 



Plate IX. 



Fig. 1 . — PmmmichiiiUs gù/an, Torrell. — 1«, Track crossing a .sand ridge. Reduced I. — 1ft, Transverse section of same. 

 Reduced J. — Ic, Track showing cross furrows. Red. J. — W, Track showing paired lobes. Red. J. — L , Track 

 with lateral furrows. Red. J. (N.B. — The track is between Ic and 2c.)— 1/ and Ig, Same in section. 

 —Ill, Track with two ridges only. Red. 1. — li. Same in section.— 1/,-, Track from tho Eophyton sandstone. 

 Natural size; after Torrell. Sec p. 157. 



Fig. 2. — ArcnkoliUs LyclH (Torrell) var. minor. — 2 «.«., 6.6., c.c. Mouths of three pairs of burrows. Reduced J. 

 From Div. Ic, Basal series. Hanford Brook. See p. 1 59. 



Fig. 3. — Armicolitcs Lydli, Torrell. Constructed from his descrij)tion. The two legs of the burrow show the 

 extremes of dimensions given by him. See p. 159. 



Fig. 4. — Armicolitcs aparmf, Salter, after Salter. Reduced I (?) — 4a, Burrow.s in sandstone of the Sti]ier stones. 

 — 46, A. paralkUus, Torrell. Constructed from his description ; the two legs of the burrow show the 

 extreme dimensions he gives. See p. 1.59. 



Fig. b.—ArcnicolitO! didijmus, Salter, after Salter. Reduced, I (?)— 5a, Burrows with those of A. sparsus—bb, A. 

 jmrallcllm, Torrell. Small variety constructed from his description. See p. 159. 



Fig. 0. — C/ioîidnfcs from Cambrian sandstones of Wales (Harlech?) After Salter. See p. 159. 



