CONCLUDING REMARKS. 221 



therefore be found to be remedied to a large extent in the complete work, the 

 publication of which, owing to the lamented death of its accomplitshed author, has 

 natui'ally lapsed, ^ve trust only for a time. 



As the greater part of the present Monograph had apjieared l)efore Eastman's 

 ' Translation ' was published, I was imable to make use of Hyatt's revised classifi- 

 cation contained in it, wdiich is here briefly outlined. As in the ' Genera of 

 Fossil Cephalopods,' the structure of the siphuncle constitutes the leading feature 

 of the larger divisions (sub-orders) of the Nautiloidea. Those forms having long 

 septal necks or " funnels " which completely close the spaces between the septa, 

 HoLOCHOANiTES, include Enducrras, Piloceras, and other genera. Under the sub-order 

 MixocnoANiTES, Choanoceras, Ascoceras, Mesoceras, etc., are placed. Cunocer(if<, with 

 some other aberrant genera, is put into the sub-order Schistochoanites. Oktiio- 

 CHOANiTES includes a great nmnber of genera, of wdiich only a few can be named : 

 OrtJwceras, Litnitcs, Gli/donautilus, Vestinautilus, Horcocerm, fiolcnoclieilns, Acanthu- 

 nautiln-s, Nautilus, and many others. Under Cyrtochoanites (in which the shortness 

 of the septal necks is the leading feature), Loxoceras, Actinoceras, Ouceras, I'oterio- 

 ceras, Gomphoceras, Phrai/moceras, and other genera are comprised. 



In the Ammonoidea we are here concerned only with the primitive group of the 

 Goniatites ; these are arranged by Hyatt, together with the Ammonites, under new 

 sub-orders, as follows : — Gafitrocampijli^ ( = Clijmcjiia of former systems), Micro- 

 campyli, Mesoeamjii/li, Eurycampyli, Glossocampyli ( = Goniatites [excepting 

 Prolecanitidaj] of former systems), Ducocampyli ( = Ceratites of former systems), 

 Phyllocampyli (including Prolecanitidae, Noritidse [Waagen], Medlicottidis), 

 LeptQcampyli, Fncltycampyli ( = Ammonites of former systems). 



G'«.s-//-yC(n;/jj//Z< is the equivalent of von Zittel's Intnisiphonata ; the rest of the 

 sub-orders are naturally included in his EcdrHsiphunntd. 



The method of arrangement of the species described in this Monograph may now 

 ])e ex2)laiued. The subdivisions of the Orthoceratidie proposed by Hj^att in his 

 provisional classification contained in the ' Genera of Fossil Cephalopods,' and 

 founded mainly upon the external features of the shell, its ornamentation, shape, etc., 

 met with only partial acceptance, owing to the difficulty of strictly limiting tlie 

 genera, especially when forms of a transitional character had to be dealt with. It 

 was therefore not adopted in this Monograpli, in wluch the Orthoceratidaj are 

 primarily divided into Lunijicu)ics and lircLnruiu/f^,- tlie former being again divided 

 into groups and sulj-groups according to the ornamentation of the test and the 

 structure of the siphuncle. In this group the seiJtation appears to be the least 

 useful of the characters to ho employed to differentiate its various elements, the 



' "The suffix campi/ius, siguifyiug curve, in the uiimes of tlie sub-nrdcrs, is used \vhi)lly witli 

 reference to the saddle iuflectious as they appear iu the typical forms of each group." 



- Barraude, ' Syst. Sil. du la Bohcuie,' vol. ii, Texte, 1^™ Partie, Itoch. Pal., 18(J7, p. 8. 



