HEINZIID ®. 135 
CaRSTENIA GALEATA (d’Orbigny). 
Ammonites galeatus VOrbigny, 1842, Voyage dans l Amérique méridionale, Vol. ITI, 
pl. 17, figs. 3-5 (not figs. 6, 7). 
Pulchellia caicedi Gerhardt, 1897, Neues Jahrb. fiir Min., Geol., und Pal., Beil.-Bd. 
Xa; p: L51, pl. 3, fig. 7. 
This species has a form, costz, ventral channel, and outer tubercles 
similar to those of C. caicedi Karsten, but having the single coste: appearing 
later, the double outer line of tubercles disappearing at the same time, and 
no median lateral line of tubercles apparent in d’Orbigny’s figures. The 
double outer tubercles are observable in figures given by d’Orbigny at the 
beginning of the outer volution and are quite plain upon an excellent cast 
of this fossil from Chile in De Koninck’s collection in the Museum of 
Comparative Zoology. Figs. 6 and 7 of d’Orbigny are true Pulchellia, not 
the young of this species. Pu. caicedi Gerhardt has exactly the form and 
aspect of the next younger parts of the volution figured by d’Orbigny and 
observable on the last mentioned. 
GERHARDTIA n. gen. Hyatt. 
The near alliance of this genus with Heinzia becomes apparent upon 
comparison of the type Gerhardtia galeatoides (Karsten) with Heinzia 
provincialis (V’Orb.) and Heinzia ? tuberculata. The umbilical characters 
are similar so far as the amount of involution and the general aspect is 
concerned, but the umbilical shoulders are more prominent, the umbilical 
zone is sometimes concave, broader, and the umbilicus deeper. The shell 
in the neanic and adult stage is more compressed and more involute than 
it is in Heinzia at the same age and also more involute than its own 
ephebic stage. The extreme decrease of involution in old specimens may 
also be noticed in these forms. The costz in the neanic stage are much 
finer and more closely crowded than in any genus of this group. The 
costee are similar, but the outer row of double nodes are absent or only 
very faintly expressed. The sutures are more complex in outline, but of 
the same general type. 
'The form is more compressed, the venter more contracted, and practi- 
cally bounded by the elongated single nodal termini of the coste. The 
furrows between the costze cross the venter, cutting it up into flexures, and 
the ventral channel is very broad and affects the flexures only, not descend- 
ing to the level of the ventral furrows. 
