Bulletin of the American Museum of Natural History Volume 20 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1904 edition. Excerpt: ...and Pleistocene. ' Characters.--Three upper premolars which are all simple, two or one principal cusp; molar crowns-higher than in Tagassu and composed of two more or less well-defined transverse crests; basal cingulum in both molars and premolars strongly developed; length of diastema between p' and c but little greater than length of premolar series. Prosthennops Matthew and Gidley. Distribution.--South Dakota, Nebraska, and probably western United States in general. Horizon.---Upper Miocene. C haracters.----Three upper premolars all smaller than molars, less progressive than in Illylohyus; canines small and more curved than in Tagassu; incisors vestigial; muzzle in front of premolars somewhat longer than in Tagassu, but much shorter than in.M3/lohyus; diastema between p' and c about one and three sevenths the length of the premolar series; molars tending to become multicuspid; malar bones developed into widely expanded massive tuberosities. The foregoing genera are readily distinguishable from Perchaerus and other Oligocene genera, in which the teeth are all more primitive. In Perchmrus p' is usually present, and all three incisors are strongly developed. The muzzle is short, there being little or no spacing between the forward teeth. Molars are always simple quadricuspid, premolars bicuspid and never molariform. In the later Dicotylines the premolars became successively rnolariform (cf. Perissodactyls), showing in the different genera various stages of molarization as was observed by Cope. Article XXIII.--ANTS FROM CATALINA ISLAND, CALIFORNIA. By WILLIAM Monro: I/VHEELER. The following eight species of Formicidae were collected on Catalina Island, California, during the spring of 1904, by Prof. C. F. Baker of...