104 The Anwrlraii (rt'ohxihi. K.Onuary, 1893 
Flu. 3. Lo)u-li()(}oiiui>i (liimal.tis Am;. 
Loirer Siluriaii species. 
1. Lonehodomas affinis Aug. 
2. ■■ farinatus An^. 
3. " cras^sirostris Aug-. , 
4. ■' doniatu.'* Ang. 
5. " Jugatus Ang. 
6. ■' macalliimi Salter. 
7. Ampyx? macconochiei Etheridge c<: Nicholson. 
8. Lonchodomas rostratus Sars. 
9. Ampyx normalis Billings. (Head only ; cf. Ainpy.r mslratus Sars.) 
10. Ampyx Ifeviusculus Billings. (This is probably the tail of Amptfx 
rostratus Sars. 
11. Lonchodomas longirostris P]ich.. cf. I., dflinis Ang. 
Genus Ami'^x, Dalnimi. ]S2S. 
Diagnosis. — Entire form ovnl. :i[)proac'hinu the form of a 
lozenge. Trilobation marked in all it.s extent ; the head is sub- 
triangular, rarely provided with a limb but usually' armed with 
long pointed spines. The glabella is generally distinctly defined 
by the dorsal furrows. Avhich form :i .salient frontal lobe before 
the contour of the cheeks. In the section Brei-if routes the gla- 
bella is oval, terminated in front l»y a long pointed rounded spine 
as in Ampfj.r nndus Murch, and .1. lostotns Boeck, &c. In the 
section Longifrontes the glaV)ella is obtuse-obovate with an abrupt 
spine as in Ampi/.r nasutiis Dalm. In the section Lonchodomas 
the glabella is lanceolate in form terminating in an elogated pris- 
matic spine as in Ampg.r rosfrafns Sars. The number of the side 
furrows on the glabella varies much from three pairs as in Ampyx 
nianimillntus Sars, to two in Ampi/.i- mnlns Murch, Ampij.r ixisiUus 
Dalm. These furrows appear to be absent in the type of the 
section LonchodoiiKis, Ampij.r r(>striitn.'< Sars. The summit of the 
facial sutures occupies a maririnal place and is hid under the 
