519 



of the arteries of this same fish in my earlier work (Allis, 1908) 

 differs in several quite important particulars from the one here given, 

 the earlier diagram having, unfortunately, been based, either on a quite 

 exceptional individual or on a description replete with errors. 



If the diagram, as here given, is compared with the diagrams 

 given in my several earlier works on this same subject, it is seen that 

 in the adults of all the elasmobranchs considered, without exception, 

 the lateral dorsal aortae of opposite sides are united by anastomosis, 

 in the median line, posterior to the point where these aortae are 

 joined by the efferent mandibular arteries. In the adults of all the 

 ganoids considered this anastomosis is not found, nor is it found in 

 the adults of Polypterus, Ceratodus, or Ameiurus. In Callorhynchus 

 also, of the Holocephali, it is not found, according to Parker's (1886) 

 figure of the arteries in this fish. In the teleosts that I have con- 

 sidered, excepting only Ameiurus, it is, perhaps, found, but there is 

 some question as to whether this teleostean anastomosis is strictly 

 homologous with the elasmobranchian one, or not. 



Men ton, Palais de Carnoles, May 12, 1911. 



Literature. 



'08 Allis, E. P. jr., The Pseudobranchial and Carotid Arteries in the 



Gnathostome Fishes. Zool. Jahrb., Abt. f. Anat. u. Ontog. d. Tiere, 



Bd. 27, 1908, Heft 1. 

 '89 Ayers, H., Morphology of the Carotids, based on a Study of the Blood 



Vessels of Chlamydoselachus anguineus. Bull. Mus. Comp. Zool. 



Harv. Coll., Vol. 17, 1889, No. 5. 

 '10 GooDEY, T., A Contribution to the Skeletal Anatomy of the Frilled 



Shark, Chlamydoselachus anguineus Gar. Proc. Zool. Soc. London, 



Part 2, 1910. 

 '86 Parker, T. J., On the Blood-vessels of Mustelus antarcticus. A 



Contribution to the Morphology of the Vascular System in the 



Vertebrata. Transact. Zool. Soc. London, Vol. 12, 1886. 



