02 
AUG. F. FOERSTE 
Among the living algae most closely resembling the fronds of 
Leveilleites in general outline are Leveillea jungermannoides 
(Mart. & Her.) Harvey and Polyzonia elegans Suhr. Both belong 
to the family Rhodomelaceae of the class Rhodophyceae, or 
Red Algae and both occur in the waters off Mauritius. The first 
of these species is figured by Engler and Prantl in Die Naticr- 
lichen Pflanzenfamilien (I Theil, 2 Abtheilung), on page 463 of 
their volume on Algae, a generic description being given on .the 
following page. Since the resemblance in general outline is 
quite striking, the term Leveilleites is here proposed for the Cana- 
dian frond-like expansions here described, without intending to 
convey any belief that these Canadian forms are algae. 
The genus Caulerpa, belonging to the class Chlorophyceae, 
or Green Algae, also presents lobate frondose expansions; this 
is true especially of Caulerpa crassifolia (Ag.) J. Ag., shown on 
page 136 of Engler and Prantl, but this is a mmch larger form 
than Leveilleites. 
Among Hepaticae, there are foliose species of Calypogeia 
(= Kantia), Lophocolea, Chiloscyphus, etc., but Hepaticae 
probably were not in existence in Silurian times; at least they 
are not known to have occurred in the Silurian. 
The genotype of Leveilleites is Leveilleites hartnageli Foerste. 
Leveilleites hartnageli Sp. nov. 
Plates IV -XI 
Type. — Specimen (plate IV, fig. A) 70 mm. in length, con- 
sisting of a stipe over 40 mm. in length, to which 12 or more 
frond-like expansions are attached. The frond-like expansions 
are about 20 mm. in length and from 3 to 4 mm. in width. The 
median line of the expansions is occupied by a narrowly linear 
black film, from one-third to two-fifths of a millimeter in width. 
In its present state of preservation, the divisions between the 
lateral lobes continue almost or quite to the continuous median 
black film. The number of lateral lobes of the frond-like ex- 
pansions varies from 6 to 8 in a length of 10 mm., 7.5 lobes being 
the most frequent number. 
