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Show 1 9 0 4 . ] ON ENTOMOSTRACA FROM NATAL. 121 (5) The anterior abdominal vein always arises from one afferent renal, rarely from both as in the Samians. Frequently, also, it is double. (6) The existence of veins continuing the azygos posteriorly is usual. Facts which are of importance for the systematic arrangement of genera and species within the family Boidse :- (1) The Boinse (Eunectes and Eryx) differ from the Pythoninse (Python) in that the intercostals are posteriorly paired arteries, while in the Pythoninte a single median artery divides into two close to the median dorsal line throughout the series. (2) The three species Eryx conicus, E. johni, and E. jaculus differ from each other in a large number of anatomical features. Besides these points several other anatomical features are of interest as new or rare among Ophidia. Such are (1) The continuation of the afferent renal of the left kidney in Zamenis gemonensis beyond the kidney into the parietes, as in Chamaeleon and Pygopus. (2) The origin of oesophageal arteries not only from the left aortic arch but from some of the intercostals of the right half arch. (3) The fusion of some of the anterior intercostals in Eryx jaculus (and Python spilotes) to form a continuous longitudinal trunk lying dorsally of the aorta. (4) Representatives of the lateral abdominal vein of Lizards appear to exist in certain snakes (e.g. Eunectes and Eryx). (5) Origin of a fat-body artery in Eryx johni from an intercostal. 4. On Entomostraca collected in Natal by Mr. James Gibson. B y G. S t e w a r d s o n B r a d y , M.D., LL.D., D.Sc., F.R .S ., C.M.Z.S. [Received March 25, 1904.] (Plates YI.-VIII.*) For the opportunity of examining and describing these species I am indebted to the kindness of Mr. James Gibson, Resident Magistrate at Greytown, by whom they were collected in the summer of 1902. All are freshwater species, and were found in pools in the neighbourhood of Greytown, Natal. The identity of some of them with European forms is a point of considerable interest, and indeed the general aspect of the gatherings is quite * For explanation of the Plates, see p. 127. |