Sphaerechinorhynchus serpenticola sp. n. is described from 17 specimens recovered from the mesenteries surrounding the large intestine of an Asian cobra, Naja naja, collected near Jesselton, North Borneo. It differs from S. rotundocapitus (Johnston, 1912), the only other species in this genus, in the number of cement glands, the number and size of proboscis hooks, lemniscus length, and shape of the posterior end of the female. The subfamily Sphaerechinorhynchinae is recognized, on biological and morphological grounds, as an aberrant group within the Plagiorhynchidae. This report is based on a number of acanthocephalans taken from the mesenteries surrounding the large intestine of the Asian cobra, Naja naja (Cantor). The collection was made by the junior author while associated with U. S. Naval Medical Research Unit No. 2, Taipei, Taiwan, on an expedition to North Borneo related to a broad project of investigation of parasites of man and lower vertebrates of Southeast Asia. Materials and methods are the same as those reported previously (Schmidt and Kuntz, 1966). A total of 17 specimens was removed from the mesenteries of a male Naja naja collected 11 October 1960, at Jesselton, North Borneo. This host was also infected with spargana (Spirometra), which occurred throughout the body cavity, and nematodes were removed from the liver (larval ascarids), lungs (Rhabdias), and small intestine (Ophidascaris). The following description is based on these 17 Received for publication 18 April 1966. *This study was supported by funding under Public Law 480, Section 104(c) and through funds provided by the Bureau of Medicine and Surgery, Navy Department Work Unit MF 022.03.07-2003. The opinions and assertions contained herein are those of the authors and are not to be construed as official or reflecting the views of the Navy Department or the Naval Service at large. t Department of Zoology, Colorado State College, Greeley, Colorado. + Department of Parasitology, U. S. Naval Medical Research Unit No. 2, Taipei, Taiwan, Republic of China and Southwest Foundation for Research and Education, San Antonio, Texas. nearly adult specimens. Drawings were made with the aid of a camera lucida and a micropr jector. All measurements are in microns unless otherwise stated. Sphaerechinorhynchus serpenticola sp. n.