Pitelka 1946 Oct. 3 to make arrangements for our departure south- ward by rail on the following day. Guaymas, itself an unattractive city, is located on a beautiful, well-enclosed bay which provides an excellent harbor. To the south of the city in the bay is a small rocky island covered with a dense growth of organ-pipe cactus, a type which occurs only scatteredly on the nearby neighboring hills, or the entire region, for that matter. The island is inhabited by a colony of cormorants, apparently [illegible] auritus, and it would appear that the growth of the cactus is related to the guano deposited by the birds. Parts of the plants used as perches and much of the covered visible ground was white with guano. We observed willets, Heerman gulls, green heron, great blue heron, brown pelicans. Oct. 4 left Guaymas by rail for a short distance, 7 hours or so, southeastward to Empalme about 7 in the morning, to a junction with the main line from Hermosillo southward. Here we boarded our Pullman car, but soon learned that departure would be delayed because of a wash-out on the r.r. track on this side of the Rio Yaqui and in Ciudad Obregon. In the night there was a heavy thunderstorm which continued south quite long after it had subsided at Guaymas. In the late afternoon we hunted on the flats north of the station along the