1904.] ON ENTOMOSTRACA FROM NATAL. 121 



(5) The anterior abdominal vein always arises from one aflferent 



renal, rarely from both as in the Saurians. 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 Boinge {Eunectes and Eryx) differ from the Pythoninse 



{Python) in that the intercostals are posteriorly paired 

 arteries, while in the Pythoninse 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 Chamceleon and Pygopus. 



(2) The origin of oesophageal arteries not only from the left 



aortic arch but from some of the intercostals of the right 

 haK arch. 



(3) The fusion of some of the anterior intercostals in Eryx 



jaculiis (and Python spilotes) to form a continuous longi- 

 tudinal 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. 

 By G. Stewardson Brady, M.D., LL.D., D.Sc, F.R.S., 

 C.M.Z.S. 



[Received March 25, 1904.] 

 (Plates YI.-YIII.*) 



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 Plate,?, see p. 127. 



