"A New Subspecies of the Black Myotis (Bat) from Eastern Mexico" by E. Raymond Hall and Ticul Alvarez is a scientific publication written in the early 1960s. This work is a detailed taxonomic analysis of a newly identified subspecies of the black myotis bat, specifically from eastern Mexico. It chronicles the findings based on recent collections of bat specimens, expanding the known range of the species. The book mainly focuses on the description and classification of the new subspecies, designated as Myotis nigricans dalquesti. It includes detailed morphological measurements and comparisons with related subspecies, underscoring the distinguishing characteristics of dalquesti, such as its size and certain cranial features. The publication also highlights the significance of the collection efforts and acknowledges contributions from various individuals and institutions. Through precise scientific observations, the authors provide insights into the biodiversity of bats in this region and the importance of continued research in understanding species variations. (This is an automatically generated summary.)