finer and extend farther back on the anterior end. The annular lines and interspaces are also finer and more irregular."
Several specimens, among the many found subsequent to 1911, preserve some of the structure features very well, and illustrations were prepared by Doctor Walcott to show them. However, it is very doubtful whether the forms shown on plate 9, figures 2 and 4, belong to this species.
Plesiotypes.—U. S. N. M., Nos 83939a-g.
PIKAIA Walcott 1911
PIKAIA GRACILENS Walcott
Plate 8, figs. 4-5
Original description.—"Body elongate, slender, and tapering at each end. It is formed of many segments that are defined by strong annular shiny lines. Head small with two large eyes and two tentacles as shown by figure 1. Back of the head the first five segments carry short parapodia that appear to be divided into two parts.
"The enteric canal extends from end to end without change in character. It is relatively large along the central portions and tapering toward the ends. Judging from such specimens as the one illustrated by figure 2, its annulations correspond in size with those of the body.
"Surface apparently smooth. Two entire adult specimens and several fragments of others indicate a length of about 5 cm."
Two additional figures are presented at this time.
Plesiotypes.—U. S. N. M., Nos. 83940a-b.
SELKIRKIA Walcott 1911
SELKIRKIA MAJOR (Walcott)
Plate 10
- Orthotheca major Walcott, 1908, Canadian Alpine Journ., vol. 1, p. 246, pl. 1, fig. 11.
- Selkirkia major Walcott, 1911, Smithsonian Misc. Coll., vol. 57, p. 120, pl. 19, fig. 6.
This species was first described from the Stephen formation on Mount Stephen. Later Doctor Walcott found apparently the same shell at the Burgess Pass quarry, but in this instance the soft body of the animal was preserved and therefore, in the 1911 discussion, he removed it from the Hyolithidae to the polychaetous annelids.
Photographs of two exceedingly well preserved individuals with the body extending beyond the shell are printed here for the first time.
Plesiotypes.—U. S. N. M., No. 83941a-b.
