1884.] ON AN ABDOMINAL VEIN IN ECHIDNA. 553 



The facts contained in this paper appear to me to be an additional 

 reason for uniting together the Storks and Herons more closely 

 than was done by Garrod ; and the classification adopted by Mr. 

 Sclater in the most recent edition of the ' List of Animals,' so far 

 as this is concerned, expresses the facts. But it might be advisable to 

 separate Scopus as the type of a family Scopidse, equivalent to both 

 the Ardeidse and the Ciconiidse, and to place it between them as an 

 indication that it forms a connecting link. It is not impossible that 

 Balceniceps should also be included in this family. 



4. Note on the Presence of an Anterior Abdominal Vein in 

 Echidna. By F. E. Beddard, M.A., F.R.S.E., Prosec- 

 tor to the Society. 



[Keceived November 11, 1884.] 



Although several excellent memoirs upon the various systems 

 and organs of Echidna have from time to time appeared, there 

 remain a considerable number of details of the structure of this most 

 interesting mammal that require investigation. The death of the 

 female specimen lately living in the Society's Menagerie has given 

 me the opportunity not only of preserving certain parts for histological 

 examination, but also of studying the anatomy of the animal in a 

 fresh condition. In this way I have been able to make out a 

 structural point which I believe has not been yet recorded, and which 

 appears to me to be of some interest — that is, the presence of an 

 anterior abdominal or persistent allantoic vein. 



In the excellent account given by Prof. Balfour, in his ■ Compara- 

 tive Embryology,' of the development of the venous system in Verte- 

 brate, I find the following statement; — "The venous system 1 of 

 mammals differs in two important points from that of Reptilia and 



Amphibia The anterior abdominal vein is only a foetal 



vessel forming during foetal life, the allantoic vein." With regard 

 to its subsequent history in Mammalia, Prof. Balfour says 2 : — " The 

 allantoic (anterior abdominal) veins are originally paired. They are 

 developed very early, and at first course along the still widely open 

 somatic walls of the body, and fall into the single vitelline trunk in 

 front. The right allantoic vein disappears before long, and the 

 common trunk formed by the junction of the vitelline and allantoic 

 veins becomes considerably elongated. This trunk is soon enveloped 

 by the liver ... At the close of foetal life the allantoic vein becomes 

 obliterated up to its place of entrance into the liver . . . Owing to 

 the allantoic (anterior abdominal) vein having merely a foetal 

 existence, an anastomosis between the iliac veins and the portal 

 system by means of the anterior abdominal vein is not established." 



In the Reptilia and Amphibia, on the other hand, the anterior 

 abdominal veins are represented in the adult condition as well as 

 during fcetal life. 



In the Amphibia, ns in the Mammalia, there are at first two abdo- 



1 Comparative Embryology, vol. ii. p. 541. s Ibid. p. 548. 



