i i 1881 PK \ i 



/>, r, !/>,/, i ,-,//-//'//"/</. / , lUt 



Family II. SKI-MI, i:. Eyet ooTered b\ skin; littoral, i; 



ov:il. with loiio- lateral tins, uniting- In-hind ; mantle -iipp 

 cartilaginous tubercles littin- inh, BOCkett -n tin- 04 

 siphon : .-inns \villi sucker^, tentacular arm^ entire) tile; 



siphon valved. Shell (cuttle-bone, sepion r sepiostaire) bi 



ll;it, thickened internally by numerou> pl:it > ; termiiK't in^r behind 

 in :i hollow, imperfectly cli:iiiil>criM| : iprx of iniicm, withoiii 

 iHM-tiiiii siphon. 



K.-iinilv 1-J. r.Ki.osKi-im.i:. ( r<,ssil only.) Sh.-ll likr S- //</. lnt 

 tlu- walls of the chambers of thr nnicro picrccil liy sm;ill ||. 

 in<lic:itin^ tin- existence of a coniifd iur siphon. Animal un- 

 known. 



Family 1:5. UKI.KMNITI iu:. ( Fossil only.) Animal, arms wit h 

 hooks. Shell a pen (pro-oetracum) attached to a ehanil>ere<i cone 

 (phragmocone), the partitions ol' which are pierced ly a >nl- 

 mar^inal. vent rally-[)laced siphnncle ; at the hiinlor end the 

 [)hraiZ - niocone is eiiveloi>ed ly a rostrum. 



Family 14. SI-IRULID^:. Animal, body oblong, with minute 

 terminal tins; mantle supported by ;i cervical and two ventral 

 ridges and grooves; arms with six rows of minute cups, tenta<-n- 

 lar arms elongated : siphon valved. Shell spiral, whorls on the 

 SMIIH- plane, not in connection, chambered ; chambers eoniieeted 

 by a ventral siphon, invested by a series of cone->haped tnbrs. 

 one for each chamber. The shell is placed vertically in the end 

 of the body, ami is held in place by side Haps of the mantle. 



I have adopted the above succession of families as indieatin- 

 a progression from the so-called naked octopods with the inter- 

 nal shell represented by cartilaginous styles, through the car- 

 tilairinous-shelled cirroteutliis, to the decapods with horny p 

 then tho>e with eal<-areous plates and minute initial chain: 

 the latter of which --i-adually b.-come larger, are -i 

 curve, become >i>iral and thus form a |.as-ai:' into the 

 tetrabranchiates and the externally shelled Nautilu-. It i- not 



Impossible, that, among the ancient genera, the -tructure of the 



animals was such as to bridge over the ^ulf which n 

 between the two orders, and it has beni recently maintained by 

 M. Munier-Chalmas. an<l more cautioii-ly advanced by I h. I'aul 



