TWO UNDESCRIBED SPECIMENS OF CASTOROIDES OHIOENSIS FOSTER FROM MICHIGAN
There are two specimens of Castoroides ohioensis in the collection of the museum of geology, University of Michigan, that were found in the state and have not been recorded. One of these was discovered near Owosso, Shiawassee County, in December, 1892, by A. G. Williams. It is represented by the base and upper part of the right mandible with the incisor and all of the molar teeth in position, the base of the left mandible, and the left incisor tooth. The incisors are well preserved and show the longitudinal striæ and cutting edge, but the tip and base of each are broken. The row of molar teeth is 75 mm. long.
The second specimen, a skull without the mandibular bones, was exhumed in a tamarack swamp in Pittsfield township, Washtenaw county, by J. B. Steere, in 1902. It was lying on a bed of gravelly marl and beneath three feet of peaty soil. The skull is hard, of a rich dark brown color, and is little damaged. The left zygomatic arch is broken, and the teeth, with the exception of the last molar on the left side and the right incisor tooth, are missing. Nearly the full length of the right incisor is represented, the only damage to the tooth being an injury to the outer surface and the loss of a few millimeters from the base. The double nature of the internal nasal orifices is well shown. The measurements are as follows:
Mm.
Length of skull from occipital angle to forward end of nasals....................................................................................................................................................................................................................................................280
Length of skull from occipital angle to forward end of maxilliaries....................................................................................................................................................................................................................................................293
Width of skull across occiput....................................................................................................................................................................................................................................................168
Width of skull across zygomatic arches....................................................................................................................................................................................................................................................230
Height of skull at occiput....................................................................................................................................................................................................................................................68
Height of skull at last molars....................................................................................................................................................................................................................................................98
Length of nasals....................................................................................................................................................................................................................................................116
Greatest dimensions of zygomatic arch....................................................................................................................................................................................................................................................67×115
Width of occipital foramen....................................................................................................................................................................................................................................................36
Length of molar tooth row....................................................................................................................................................................................................................................................73
The writer is indebted to Professor E. C. Case, of the department of geology, University of Michigan, for permission to publish these records.
Norman A. Wood
Museum of Zoology,
University of Michigan
