BRACHIOPODA. 347 
Glosslna.] 
We have two imperfect and exfoliated specimens which appear to be of this 
species, Lingula covingtonensis Hall and Whitfield is sometimes regarded as iden- 
tical with L. cohourgensis. An examination, however, will show that it is more 
broadly oval and has sharply elevated, rather distant, concentric lines. The stria* 
in L. cohourgensis are fine, elevated, sharp and closely crowded on the lateral slopes, 
while medially there are fine concentric undulations with occasionally some radi- 
ating lines. 
Formation and locality. — Rare in thi; Trenton liniL'Stone at Minneapolis and CiiatlleUi, Minnesota: 
Cobourg and Collingwood, Canada. 
Collectors.— IL. V. and N. H. Winchell. 
Mus. Reg. Nos. 309, 3504. 
Sub-genus GLOSSINA, Phillips. 
1848. Glossina, Phillips. Memoirs of the Geological Survey of Great Britain, vol. ii. pi. ii, p. .370. 
1892. Glossina, Hall. Pala'ontology of New York, vol. viii, pt. i, pp. 5, 6, 1."). 
Species of this sub-genus differ from Ldngula in having "an acuminate or sub- 
triangular form, in which the rostral area is very narrow, with long, sloping post- 
lateral margins, and a rounded or transverse anterior margin." (Hall, op. cit. p. 5.) 
This sub-genus is restricted to Palaeozoic rocks, 
Lingula (Glossina) hurlbuti N. H. Winchell 
PLATE XXIX. FIGS. 13 aiul 14. 
1880. Lingula hurlbuti N. H. Winchell. Eighth Annual Report of the Geological and Natural 
History Survey of Minnesota, p. 62. 
Original description: ' Shell ovate, broadest in the anterior half, and pointed 
posteriorly; the sides approaching the apex with a gentle convexity; lines tangent 
to sides at one-third the length from the apex, form an angle of 72''; anterior 
angles obsolete. The exterior surface of the shell is marked by sharply elevated 
concentric plications, which stand perpendicular to the shell, and on the anterior 
third portion five occupy the space of one line, but towards the beak they are 
reduced in size and increase in frequency so as to become mere stria\ Where these 
are largest and perfectly developed, the intervening grooves are destitute of fine 
striations. These plications leave corresponding lines on the interior cast when 
the shell is exfoliated. There are no longitudinal radiations visible on the exterior, 
but on the cast near the front are exceedingly dim, interrupted lines visible under 
the lens, that possibly have the same origin, but these do not extend more than a 
line and a half from the front margin, and they cannot be seen even with the lens 
except under a favorable angle of reflected light. 
