172 
NAUTILOIDEA. 
Actinoceras remotiseptum. Hall, sp. 
1848. Ormoceras remotiseptum, Hall, First Regent’s Rep. upon the 
New York State Cabinet of Nat. Hist. p. 173, pi. iv. f. 3. 
Sp. Char. ‘‘Cylindrical, gradually tapering; septa moderately 
convex, distant half the diameter of the tube ; siphuncle eccentric, 
large, swelling moderately between the septa, and but slightly con- 
tracted at the junction of the se^ita ; character of the external 
surface unknovrn. 
“ The specimen described is a fragment which is worn down through 
the centre of the siphuncle. The proportions of this part of the 
fossil and the great distance of the septa contrast very strongly 
with the Ormoceras [Actinoceras'] tenuijilum and with other known 
species of the genus.” {Hall.) 
Beinarlcs. There is very little doubt in my mind that Endoceras 
clistans, Hall (Pal. of New York, vol. i. p. 220), is conspecific with 
the present species ; probably the marginal position of the siphuncle 
led to the former species being placed in the genus Endoceras. 
Horizon. Trenton Formation (=Bala Limestone Group). 
Loccdity. Canada, or United States ; probably the former. 
Represented by a single example, presented by J. Welsh, Esq. 
Actinoceras Richardsoni, Stokes. 
1840. Actinoceras Ricliardsoni, Stokes, Trans. Geol. Soc. ser. 2, vol. v. 
pt. 3, p. 708, pi. hx. flp. 2, 3. 
? 1838. Conotuhularia Cuvieri, Troost, Mem. Soc, Geol. de France, 
tom. hi. lJ“e partie, p. 88, pi. ix. f. 1. 
? 1866. Orthoceras {Actinoceras) Richardsoni? , Ban-aude, Syst. Sil. de 
la Boheme, vol. ii. Texte hi. 1874, p. 737, pi. ccxxxiv. tf. 2, 3. 
Sp. Char. Shell apparently slowly tapering. Section probably 
circular. Septa approximate ; 4 lines distant where the shell has 
a diameter of 3 inches, arching strongly upwards. Siphuncle mar- 
ginal, very large, its diameter nearly one half that of the shell ; the 
interior filled with calcareous, vertical lameUse, radiating from the 
endosiphon, and abutting against the walls of the siphuncle. A 
horizontal row of foramina are often seen upon the segments of the 
siphuncle, for the passage of the tubuli given off from the endo- 
siphon. The surface of the test is ornamented with rather regular 
undulating, transverse, upwardly imbricating striae. 
Remarhs. The type of this species is very imperfect and much 
abraded. It consists of a longitudinal section, exposing to view the 
septa and siphuncle. Stokes has figured only part of the specimen. 
