ON THE AORTIC LIGAMENT IN INDIAN FISHES. 61 



5. On the Aortic Ligament in Indian Fishes. By D. R. 

 Bhattacharya, M.Sc, Zoological Department, The 

 Muir Central College, Allahabad, India, U.P.* 



[Received December 9, 1919 : Read February 24, 1920.] 

 (Plates I. & 11. t and Text-fig'ures 1-5.) 



Contents. Page 



I. Introduction 61 



II. The Aortic Ligament in Fseudeutrojoius garua taken as 



a Type 62 



1. The Disposition and Attachments of the Ligament ... 62 



2. The Grross Structure and Histology of the Ligament... 64 



III. The Ligament in other Fishes 67 



IV. The Occurrence and Absence of the Ligament in various 



Fislies 68 



V. Some Suggestions concerning the Role and Relationships 



of the Aortic Ligament 69 



Appendix: Methods of Preparation of Material 70 



I. Introduction. 



The existence of a longitudinal ligament, evidently closely con- 

 nected with the aorta, and extending over its entire length, was 

 first noted by ine in the Silaroid fish, Pseudentropius garua, in 

 the year 1916. It was not, however, until some moutiis later, 

 when Dr.W. N. F. Woodland, who had independently observed the 

 same ligament in the same fish, and at the same time chanced to 

 alight upon Mr. Burne's ISTote "On Elastic Mechanisms in Fishes 

 and a Snake" (Proc. Zool. Soc. London, 1909), suggested to me 

 that the presence of a ligament actually inside the aorta was 

 sufficiently remarkable to warrant further enquiry, that I seriously 

 took up the work, and the present j)aper records my observations 

 of the dorsal aorta in over 80 species of fishes, both marine and 

 fresh- water. The short paper by Burne % constitutes the whole 

 of the literature on the subject known to me, and I have been 

 unable to discover if any other exists. Burne found that an 

 elastic ligament exists in the dorsal aorta of ClujMa alosa, and he 

 termed this ligament the " ligamentum longitudinale ventrale.'*' 

 He did not, in his Note, go into any details on the subject, and 

 only casually mentions its structure and, according to him, its 

 probable function. His conclusions, howevei', regarding the 

 function of the ligament seem to me to be doubtful. I may also 

 emphasize in this place that this aortic ligament (as I prefer to 

 call it) is not to be confused with the better known, because more 



* Communicated by W. IST. F. Woodland, F.Z.S. 

 f For explanation of the Plates see p. 74. 



X Burne. R. H., '" On Elastic Mechanisms in Fishes and a Snake," Proc. Zool. Soc. 

 London, 1909, pp. 201-203. 



