18 
of groAvtli (PI. II, Fig. 5rt)* Those of the Hanks arc not (Icci^cncd, wliile 
those of the dorsal and ventral aspects are not narrowed ; hnt a series of 
sharp ohliqne lines on the dorsal and ventral borders evidently indicates the 
presence of comparatively large and rohust ridge-scales. These scales are 
conspicnons again in No. and are shown in the outline sketch of the caudal 
pedicle in PI. II, Fig. 0 (s). Their posterior overlapping margin appears to 
he truncated, and the ridge-series at the base of the upper caudal lobe is 
supported by slender interspinous hones {b). 
AnciimoM.v.xE kobustl's, sp. nov. 
Plato y, Pigs. 2-4‘. 
Obs. — There is fragmentary evidence of a second and more rohust 
species of ArchcconKcne, which is illustrated by the folloAving four sj)ccimens : — • 
{(() The type specimen shown of the natural size in IT. A', Fig. 2. 
(i) Distorted smaller iish, very fragmentary. 
(c) Distorted caudal region shoAvn of the natural size in PI. A^, Fig. 3. 
{(J) Smaller caudal region. 
(c) Still smaller caudal region, part of the upper lobe shoAvn of three 
times the natural size in PL A', Fig. 1. 
One very large head, Avith ]>art of tlu' abdominal region, and another specimen 
showing scattered remains of the caudal region, may also pertain to this 
species ; and, if so, the fish must sometimes hav(; attained a length of not less 
than OIL 
Sp. Char. — A species commonly attaining a length of about 0'2. 
Dead Avith opercular ap^iaratus occupying about one-llfth of the total length 
of the fish, and the maximum depth of the trunk equalling nearly one-half 
of the length from the pectoral arch to the base of the caudal fin. Dorsal 
tin comjirising about t(‘ii rays, arising at the middle point hetAveen the occiput 
and the base of the caudal tin, opposite the origin of the anal tin, Avhich has 
not less than fourteen rays. Scales exhibiting only the concentric lines of 
groAA’th. 
A.rkU Skeleton of Trunk. — Nothing Avorthy of special note is to he 
observed in the head and opercular apparatus ; hut the arches of the vertebral 
column are more satisfaetorily displayed than in the examples of the last 
species. There is again no evidence of ossiilcations in the notochordal sheath, 
