Rica. The extension of the anterior symphyseal region of the mandible is short in ignavus; the specimen with the longest extension (No. 37621 from El Real), however, has the extension only barely shorter than does No. 139933 of griseus from Vijagual, San Carlos, Costa Rica. In brief, while we see the characters of ignavus as set forth by Goldman (op. cit.), we find them to be of only an average sort and not pronounced. Further, a specimen (No. 139833) from Vijagual, San Carlos, Costa Rica, provides a morphological intergrade between griseus and ignavus. Accordingly, we arrange ignavus as a subspecies of griseus; the name of the animal from extreme eastern Panamá should stand as Bradypus griseus ignavus Goldman, 1913.

Cyclopes didactylus mexicanus Hollister

Hollister (Proc. Biol. Soc. Washington, 127:210, October 31, 1914) named Cyclopes mexicanus, on the basis of light-golden upper parts and large, especially broad, auditory bullae, as specifically distinct from Cyclopes dorsalis Gray (= Cyclopes tridactylus dorsalis Gray). Our comparisons and examination of the specimens used by Hollister and a few other specimens acquired since 1914 convince us that C. mexicanus is taxonomically valid and that Hollister, in general, correctly indicated its diagnostic characters. Nevertheless, there is considerable evidence that C. mexicanus is only subspecifically distinct from C. dorsalis. In the first place, an adult C. dorsalis, not seen by Hollister, from El Banco, Chiriquí, Panamá (No. 248343 USBS), has more inflated, although narrower, auditory bullae than do specimens of C. mexicanus. In the second place, the two specimens mentioned by Hollister (loc. cit.) as from "Tabasco and southern Vera Cruz" actually are both from Tabasco (No. 100040 USBS from Teapa, and No. 100174 USBS from Montecristo). Each, as Hollister indicated, is darker on the upper parts than his other referred specimens (two others from Montecristo in Tabasco and another from El Salto in Chiapas). To us this suggests intergradation with C. dorsalis. Incidentally, the specimen that Hollister mentioned from Veracruz (No. 78111 USBS, from Minatitlan), and that he indicated as having dark upper parts, really has light upper parts. Third, a skin from Petén, Libertad, Guatemala (Harry Malleis field No. 504, immature ♀), that the late Major E. A. Goldman and one of us (Hall) once examined, has considerable dark brown on the chin, throat and midventral line, as well as a dark mid-dorsal stripe. The specimen is intermediate in color, as well as geographically, between C. t. dorsalis and C. mexicanus, although referable to the latter. Taken together, the above evidence indicates subspecific status for the northern, Mexican, animal and we conclude that it should stand as Cyclopes tridactylus mexicanus Hollister.

Transmitted July 1, 1952.