ON NASAL SECEETOET SACS IN TELEOSTEI. 54l 



On the Presence of Nasal Secretory Sacs and a JSTaso-pbaryngeal 

 Communication in Teleostei, with especial reference 

 to Cynoglossus semilcevis, Gthr. By H. M. Kyle, M.A. 

 (Communicated by Prof. G. B. Howes, Sec. Linn. See.) 



[Read 18th January, 1900.] 



(Plate 38.) 



The observations embodied in this paper have been made 

 during the course of a prolonged research into the anatomy 

 of the Plat-fishes (Heterosomata). It is considered advisable to 

 publish them separately because, though the research, is far from 

 completed, the facts to be described have a certain importance 

 apart from the main series of results. In order to carry on my 

 work successfully I spent some time at the British Museum of 

 Natural History, and I desire to acknowledge my indebtedness to 

 Mr. G. A. Boulenger, P.E.S., of the Zoological Department of that 

 Institution. Every facility was given to me for my work, and his 

 advice, generously offered, has aided me in many directions. I am 

 proud to acknowrledge also the friendly counsel and masterly 

 criticism of Prof. G. B. Howes, P.E.S., to whom indeed the 

 appearance of this paper in its present form is due. 



It is generally believed and taught that Pishes possess no 

 secretory apparatus in connection with their olfactory organs, and 

 that in the Teleostei these organs have no direct communication 

 with the mouth. These characters, and more especially Ibe 

 latter, have been considered as almost exclusively distinctive of 

 the air-breatbing Vertebrates — so much so that Huxley, in his 

 famous paper on Ceratodus Forsteri *, discussing the communica- 

 tion present in the Dipnoi, considered it necessary to raise and 

 answer the question — of what use are " internal nares " to purely 

 branchiate animals? Internal nares in water-breathing verte- 

 brates seem indeed unnecessary, because the respiratory apparatus 

 is in immediate communication with the mouth, so that where 

 they do occur a special explanation has to be sought. As 

 with the Dipnoi and Myxine, so with the case to be herein 

 described, the function of the naso-pharyngeal communication 

 seems quite clear, though its presence may run counter to our 

 preconceived notions, 



* Proc. Zool. Soc. 1876, cf. pp. 24 & 180. 



