66 The American Geologist, AnKust, i89'\ 
As iilread}" stated in the lirst article, most l)HHes api)eai- at 
first sight as stout subeircular to subovaleintiuuus rings* (of. 
pi. II, fig. 1, wiiieli is tlie base of the specimen reproduecd on 
pi. IX. fig. 1, (ij). cit.). The original form was probably cir- 
cular, as the elongated forms (cf. fig. 20) are generally found 
near the edge of the supporting fossil (cf. pi. VIII, tigs. 1 and 
2), where they wci-e more liable to l)ecome laterally com- 
pressed than those on the inner })art of the fossil. 
The dimensions of those rings which are found still attached 
to a Coitiihi rl(t are: diameter from 1 to 2 mm. ( original of fig. 
1. pi. II, measures l.;>x.7 mm.; original of !ig. 19, 1.75x2 mm.), 
though a few larger separate ones have V)een found (one 
measuring 4 mm.) : bight. 3 inm., (taken from the originals to 
figs. 1, 2 and 8). 
Externally the ring is perfectly smooth and shining (fig. 1). 
expanded more or less al)ru])tly towards the base (cf. figs. 2, 
3, 13, 18). Underneath it possesses a system of regular radial 
folds (cf. figs. 7, 8, 9, 13, 18). The true nature of the rings 
is revealed by a few vertical sections which were found on 
some slabs (cf. figs, 2 and 3). Fig. 2 is a reproduction of the 
whole fossil, which is interesting because it demonstrates not 
onl}^ the occurrence of basal appendages detached from the 
extraneous object, but also the common separation of the pyra- 
mid of Conalarid (/racilis from the appendage a little above the 
latter. As both sections are not quite median, part of the ring 
*These rings have been observed by A. G. Nathorst as early as 1882 
(cf. A. G. Nathorst. ''Om forekomsten af SplttniotlutUus cfr. aiigustifo- 
liii!^ Hall i pilurisk skifTer i Vestergotland" in Geologipka Foreuingens i 
Stockholm Forhandlingar, vol. 6, p. 315, pi 15). The same author has 
published this year, in the A|)ril number of the same journal (vol. 18, 
no. 4), under the headline of •'■SiiheiiothallnH en CoiiuJarid," a review 
of the study of this interesting fossil in Sweden, from whicli it appears 
that he, in describing — in the first cited pajjer — a specimen of Spheno- 
thalhts Hall from the Silurian shale in the neighborhood of Vaiiib in 
Westgotfiland, accepted Hall's interpretation of the fossil as an alga. 
Some year.s later, however, another specimen was sent to him by Dr. N. 
O. Hoist, the state of preservation of which was such as to convince 
Nathorst at once of the impossibility to refer the fossil to the vegetable 
kingdom. He pointed ovit this fact to Hoist, who afterwards sent the 
same specimen to J. Chr. Moberg f(M- identification. The latter reached 
the same conclusion, as appears from an extract of a letter of his to 
Nathorst: "It seems to remind me somewhat of a Conularia, and above 
all it surely was not any alga." Nathorst himself accepts now the 
identification of Sjjenotliallus with Conularia. Hall's type is not so 
well preserved as to have been able to suggest a comparison with 
Conularia. 
