Southwellia ransomi New Species

Abstract

The genus Southwellia Moghe, 1925, was established as a monobasic genus to include a species of tapeworm described as Monopylidium gallinarum by Southwell in 1921, which was collected from a domestic fowl at Berhampore, Bengal, India. Moghe, and later Meggitt, recognized the necessity of separating this species from the balance of the genus Monopylidium because of the unilaterality of the genital pores. Each of these authors has given a diagnosis of the genus based on the facts stated in the original specific description of the parasite and hence both diagnoses fail to describe certain important portions of its anatomy. In all characters of generic rank mentioned the species described below as new agrees so perfectly with S. gallinarum (Southwell) that the writer feels justified in adding to the generic diagnosis. Six generic names have been proposed for the group of species to which the above mentioned form belongs. Of these, one (Parachoanotaenia Luehe, 1910) falls immediately into synonymy for it is antedated by Icterotaenia Railliet and Henry, 1909, both names being based upon the same type, to wit: Choanataenia galbulae (Zeder, 1803). The oldest of the five names remaining is Choanotaenia Railliet, 1896, with Choanotaenia infundibulum (Bloch, 1779) as its type. The salient characters of this genus are: (1) Irregularly alternating genital pores; (2) genital canals passing between the dorsal and ventral excretory canals, and (3) the presence of a persistent uterus which may be subdivided into numerous communicating chambers. The second of the names, in point of time, is Monopylidium Fuhrmann, 1899, type species Monopylidium musculosum (Fuhrmann, 1896). This genus agrees with Choanotaenia Railliet in having irregularly alternate genital pores and in the relation of the genital ducts to the excretory ducts, but is separated from it by the structure of the gravid uterus. Here the uterus breaks down into separate noncommunicating chambers or egg capsules, each capsule containing one or more eggs. It is the contention of Clerc