FIFTH, OR AGASSICERAN BRANCH. 213 
second quarter of the fifth whorl in the St. Thibault specimen, the channel ridges 
are still raised lines marking the angular junctions of the sides and smooth 
channel areas. On the last part of the same whorl in the third specimen just 
mentioned, and in fact on the second quarter, even this angularity has almost 
wholly disappeared, the channels being obsolete, the keel therefore additionally 
prominent. The involution of the last part of the fifth whorl covers three fourths 
of the sides of the preceding whorl, exclusive of the channel area and the keel, 
which would somewhat increase this amount. 
Oppel refers this species to the young of Guibalianus, our Oxyn. Greenoughi, in 
which, however, he was probably mistaken. The specimens in our possession 
show that this species has not been correctly quoted as coming from any other 
localities than Cdte d’Or, the basin of the Rhone, and perhaps Mierlatz. . 
Sutures of the first specimen described above on the third quarter of the 
fourth whorl had lobes differing from one third to one half, and saddles about 
one third; and the third specimen on the first quarter of the fifth whorl had 
lobes differing one third and saddles a trifle less. The outlines of the suture are 
similar to those of Coroniceras and Asteroceras. Three saddles are to be seen 
upon the side, the inferior laterals being deeper than the superior laterals, as in 
other species, but the first auxiliaries are unusually large, nearly as deep as the 
inferior laterals, and very broad. The abdominal lobe, as stated, is from one half 
to one third longer than the superior laterals, and the superior lateral saddles 
about one third shorter than the inferior laterals. There is therefore no ground 
for the reference of this species to the genus Amaltheus, as has been supposed by 
some authors. According to Oppel this species is found in the Tuberculatus bed, 
and though Oppel probably never saw a true Col/enoti, this statement is approxi- 
mately correct. Dumortier’s specimens of Collenoti (Cluniacensis) were found in 
his Planicosta bed immediately above the Oxynotus bed, and all of his beds 
above the Bucklandi and Davidsoni (Striaries) beds are equivalents of the Birechii 
or Tuberculatus zone at Semur. D’Orbigny’s originals were reported as coming 
from the Gryphea arcuta beds, but this was evidently considered to be doubtful 
by Oppel, even before Dumortier found his specimens. 
The extraordinary series figured and described by Wright from the Oxynotus 
bed, under the name of Slatteri, are widely distinct. The figures of the shell and 
sutures we have quoted above are certainly taken from a species which is very 
closely allied with the true OCollenoti. It is assuredly an Arietian, with affinities 
allying it to obtuswm, and comes nearer to Collenoti than any other species in 
respect to involution, smoothness, form of whorl, and abdomen. The other mem- 
bers of Slatteri as figured are probably diseased specimens of ob/usum. 
The keel of this species was examined very carefully to determine whether 
it was solid or hollow, and it was found to be solid. 
A dwarf form of Ast. (Aviet.) stellare is figured by Geyer in his “ Lias. Ceph. 
d. Hierlatz b. Hallstadt,” and his Ast. (Oxyn.) Collenoti is certainly very similar to, 
if not identical with, the French form of that name. Asteroceras ( Arvet.) stelleeforme, 
Wih., Mojsis. et Neum., Beitr., VL, Plate XX VI, seems to be a species of this 
