In the report for 1841, Conrad proposed f f the name Dicranurus for
a fossil there figured, also from the Lower Helderberg fauna. This
form was mentioned in a list given on a preceding page of the same
report as Dicranurus hamatus and under the name Acidaspis hamata it
has become known as one of the peculiar species of this fauna. The

*De Trilobitls. p. 35, plate. Hg. 3.
t **Ueber die Triloblten," (Neues Jahrbuch Mr Mineralogie, etc).
t Orflranization der Tdlobiten, pi. 2. fisr. 11.
§ Burmeister states that this specimen in the Museum of the University of Berlin, was
the only one known of the species, and Heidenhain in 1869 makes the same statement
(Zeitsohrlft der deutschen «reoloeischen Gesellschaft. vol. 21. p. 167).
li Third Annual Report on the Palseontolofirical Department of the Survey, p. 206. fig. a
of the plate accompanying a few copies of the report for the following year. (See
Fifteenth Report N. T. State Cabinet)

II In his report for the following year Oonrad used the term Acantholoma spinosa in a
list of fossils, but without further definition.
♦♦Pals&ontology of New York, vol. 3. p. 370.
ttPacre i8, plate« flgi i*



Bepobt of the State Geologist. 65

species is not well known except from its cephalon which is notable for
the extraordinary pair of curved spines originating upon the
very broad occipital ring, making almost an entire revolution in
a spiral outward curve and resembling a pair of grappling irons. Mr.
