332 
PALAEONTOLOGY OF NEW YORK. 
Dr. Waagen has taken Norwood and Pratten’s species, Produdus splendens, 
as the type of the group which embraces his typical species, and further has 
expressed the opinion that the American species from the Coal Measures be¬ 
long for the greater part to Marginifera. It is extremely doubtful if the 
evidence will sustain this assumption though there are certain species of the 
Coal Measures, Produdus splendens, Norwood and Pratten, P. longispinus, Sow- 
erby, P. Lasallensis, Worthen, which show the characters of Marginifera in 
some stage of development. 
In the species Produdus dissimilis, Hall, # from the middle Devonian of 
Rockford, Iowa, and the upper Devonian of New York, similar internal char¬ 
acters are quite strongly developed, especially in the pedicle-valve, and in both 
valves the margins of the ridges are more or less distinctly crenulated. While 
the species has the cardinal area, teeth and sockets in an exceedingly obscure 
condition, the cardinal process is like that of Productella, strongly bifurcated 
to its base, and its external surface presents characters rarely met with either 
in Productus or Productella, but not uncommon in Strophalosia ; a spinifer- 
ous pedicle-valve, and a brachial valve without spines, but covered with con¬ 
centric lamellose ridges. 
* Mr. Walcott has proposed to change the name of this species to P. Holland (Monograph U. S. Geol. 
Surv., vol. viii, p. 130, 18S4), as de Koninck had used the same term for a Devonian species which is evi¬ 
dently a Productella. Should, however, the American species be referred to Marginifera, its original 
designation may be retained. 
