In your article “On the Move” (On the Campus, June 7), Professors Bess Ward, Michael Celia, and Lars Hedin are not standing behind the skeleton of Allosaurus in Guyot Hall. 

This skeleton is Phenacodus primaevus, a condylarth. Allosaurus is a dinosaur, a reptile from the Jurassic period. Phenacodus is a mammal from the early Eocene. Condylarths are very early precursors of hoofed mammals such as horses.

Editor’s note: Philip Gingerich ’68 and Ned Groth ’66 also wrote with, in Groth’s words, a “bone to pick” about PAW’s error.

Elizabeth Horn
Research staff, Department of Ecology and Evolutionary Biology, Princeton University