On the Genu>< AiYipy.r. — Voydes. 99 
938 [80-t c] 
I860. — Anonj-mous. Geological map of the southern part of the 
isthmus of Tehuantepec. No place of publication. 
XXIY. — ParagiKiy, Patagonia and Tierra del Fucgo. 
939 [852 a.] 
1847; — Grange (J.) Carte geologique de la Patagoine et de la 
Terre de Feu. Scale 1 : 1,150.000. 
Accompanying: -Voyage an pole sud et dans I'Oceanie, " 
par Dumont dUrville, Geologic; atlas in folio. Carte No. 2, 
Paris, 1847. 
[Notes ox Pal.eozoic Crustack.e Xo. 3.] 
ON THE GENUS AMPYX WITH DESCRIPTIONS 
OF AMERICAN SPECIES. 
By A. W. VoGDEs, Alcatraz Island, Sau Francisco, Cal. 
Historical notice of the genus Ampyx Dal man 1828. 
1828. — Dalman describes and figures the first species of tiiis genus 
under the name of J myji/.c ua.s ((</(.>« from the Lower Silurian of East 
Gothland at Sliarpasen. This new genus is classified under Section v, 
family Asaphus {Ampyx) /*a.sv(<«.s Paheaden p. 53, plate 5, fig. 3. The 
author gives the following brief description of the genus : "Eyes not 
apparent nor even protuberances in their place, but rather impres- 
sions ; head large and triangular ; glabella very large, prominent gib- 
bous, and not lobed ; thorax short with few segments (6); pygidium 
distinct and entire." This species has been described and illustrated 
by numerous authors. 
1835. — Sars describes and figures in Isis, Heft 4, p. 334, plate 8, figs. 
9 and 4, two new species from the Lower Silurian of Xorway under the 
names of Ampyx rostratas and .1. mammlllatng. The glabella of Xmpyx 
mammillatus is represented on plate 8, fig. 4c as blunt in front, less so 
in fig. 4a, and elongated in fig. 4b. It is doubtful whether all these 
figures are of the same species, Boeck, Gea Xorvegica, 1838, p. 144 ex- 
presses this view, but the author does not suggest a new name for the 
species. Angelin (Pahcontologia Scandinavica, 1854 p. 80) restricts the 
name of Ampyx mammillatus to Sars' figure 4c, and gives that of 
Ampyx costatus Boeck, to figs. 4a-b-d apparently from a term used by 
Boeck in the naming of species in the Christiania Musuem. 
1843. — Portlock in his report on the Geology of Londonderry, etc.. p. 
258, gives a generic description copied after Dalman's ; the author also 
describes and illustrates two Irish species from the Lower Silurian, 
which he considers identical with those described by Sars in 1835. 
Col. Portlock remarks: " If Ampyx nagutxs Dalm, was provided with 
a frontal spine, it is equally probable that if perfect it would have 
exhibited lateral buckler spines also, and hence these appendages 
