ART. 9 NEW CAMBRIAN CRUSTACEA — RESSEE 11 



of Tuzoia that at first sight recalls the Middle Cambrian T. pi^ae- 

 TTiorsa and the Lower Cambrian T. spinosa. It can not be confused 

 with T. retifera and it allies because of the presence of more mar- 

 ginal spines and the frill on the keel. 



Comparing T . getsi with T. spinosa, beside the common possession 

 of keel spines, we find but little chance for confusion since the latter 

 has tAvo sets of marginal spines. There is more resemblance to T. 

 praemorsa both in the shape, size, and distribution of the reticulations 

 and particularly in the scalloped frill on the keel, but right here we 

 find an easy way to distinguish the two ; T. getzl has perhaps a dozen 

 spines or scallops along the keel while T. praemorsa has only about 

 seven. 



The specific name is given in recognition of the interest of Noah L. 

 Getz in collecting the fossils, as rock was quarried on his farm, which 

 resulted in the finding of this and many other fine specimens. 



Horizon and locality. — Lower Cambrian, Kinzers formation ; (loc. 

 12x) near Rohrerstown, Pennsylvania. 



Holotype. — Cat. No. 10044, Peabody Museum, Yale University. 



TUZOIA ? DUNBARI, new species 



Plate 7, figure 1 



A single specimen from the Kinzers formation represents another 

 species that should, perhaps, be referred to a new genus. The speci- 

 men is an impression of the exterior of an extremely spinose form. 

 I am unable to decide whether this represents an entire valve, in 

 which case it, of course, belongs to a new genus, or whether it com- 

 prises only that part of the shell between the dorsal line and the keel. 



Comparing this form with the more spinose species of Tuzoia, we 

 note first the extraordinary extension of the dorsal line into long, 

 upturned spines such as we find in some living Crustacea. Assuming 

 that the longer spines occur on the rear margin and that the outer 

 edge extends only to the keel, we note the very long spine in the 

 usual position between the dorsal extension and the keel. If this is 

 only the inner part of the test one or more marginal spines should 

 occur beyond the keel. At least five spines edge the anterior margin 

 exclusive of the dorsal extension. If the foregoing interpretation of 

 the shell is correct, then the broad-based spine along the lower 

 margin belongs to the keel and would indicate the presence of a frill. 



The specific name is given in honor of Dr. Carl O. Dunbar, of 

 Yale University, who so kindly permitted me to describe this fossil 

 in this study of the group to which it belongs. 



Horizon and) locality. — Lower Cambrian, Kinzers formation : (loc. 

 12x) near RohrerstoAvn, Pennsylvania. 



Holotype.— Cut. No. 10046, Peabody Museum, Yale University. 



