Tamerlania bragai was described by Dos Santos (1934) as bragai (obvious misspelling of Tamerlania) from the kidneys and excretory ducts of domestic pigeons and chickens at Rio de Janeiro. It was reported from the pigeon in Sao Paulo by Reis and Nobrega (1936), in the Philippines by Tubangui and Masilunigen (1941), in Puerto Rico by Maldonado and Hoffman (1941) and from turkeys in Brazil by Barretto and Filho (1942). All of the Latin American authors spelled the generic name Tamerlanea and none of the accounts reported the presence of an acetabulum. The genus Tamerlania was erected by Skrjabin (1924) to contain T. zarudnyi from Passer montanus in Russian Turkestan. Khitrowo-Kalantarian (1925), from original observations and from information communicated by Skrjabin and by Issaitschikow, reported the parasite from four additional species of birds and stated that the digestive ceca unite posteriorly. Other described species include T. meruli by Nezlobinski (1926), T. bragai by Dos Santos (1934), T. japonica by Yamaguti (1935) and 7'. melospizae by Penner (1939). Yamaguti (1941) reported that T. japonica is specifically identical with T. zarudnyi. Penner formulated a key to the species of the genus, the original diagnosis of which was emended or amplified by each of the subsequent writers. Whether an acetabulum is present in species other than T. bragai remains to be determined. Skrjabin (1924) also erected the family EUCOTYLIDAE to contain Eucotyle Cohn, 1904 and two new genera, Tanaisia and Tamerlania. Two additional genera, Lepidopteria and Ohridia were added by Nezlobinski (1926). The family characters were stated by Fuhrmann (1928) and reviewed by Cheatum (1938) and Penner (1939). According to these authors the worms are monostomes, parasites of the renal ducts of birds. The family is world-wide in distribution, the hosts are chiefly migrants, and several of the species have been described on the basis of limited material. As a result, the morphology is imperfectly known and the validity of certain genera and species is questionable. In a personal communication, dated September 25, 1942, Dr. William A. Hoffman wrote that one of his students, Mr. Jose F. Maldonado, had found that T. bragai possesses a small ventral sucker. Dr. Hoffman stated that after publication of the note, Maldonado and Hoffman (1941), Mr. Maldonado had discontinued his studies on T. bragai, but that the presence of an acetabulum in the species should be of interest in determining the phylogeny of the monostomes and offered, with the reservation that the discovery of the acetabulum should be accredited to Maldonado, to place the material at my disposal. The material sent by Dr. Hoffman consisted of one mounted specimen (Fig. 1) and an incomplete set of serial sections of the kidney. The study was completed and a manuscript prepared, giving credit to Mr. Maldonado for discovery of the acetabulum. Subsequently, Mr. Maldonado returned to Puerto Rico and continued his studies on T. bragai. Fol-