79 



consist of mucous membrane and some few muscular fibres, and are 

 armed with retroflexed spiculce. These lips are in perfect contact 

 at the hinder part of the glottis when it is closed, but diverge near 

 their anterior part so as to leave a triangular open space of about 

 the size of a pea, the edges of which are incapable of being approxi- 

 mated to each other. In front of this triangular aperture, and at 

 some distance behind the tongue, (to vvhich it is connected by mu- 

 cous membrane and muscular fibres,) is an elevated substance of a 

 soft leathery texture, resembling that of the epiglottis o f Mammalia : 

 its form is triangular, the apex being inferior and connected with 

 the tongue, and the base being elevated and terminating in three 

 thin convex portions or lobes. The middle one of these lobes is 

 the largest ; it is free, and rests immediately over the triangular 

 orifice of the larynx just described, which, when depressed, it is in 

 size adapted to cover. In a line continuous with the floor of the 

 upper larynx and penetrating deeply beneath the epiglcttis is a 

 cavity or sac lined with mucous membrane. 



Having demonstrated these parts on the preparation exhibited by 

 him, JNIr. F. D. Bennett added that as it had been the opinion of 

 naturalists in all ages that no bird pcssesses an epiglottis, the 

 structure which he had brought under the notice of the Society ap- 

 peared to him highly interesting. So fixed was the OĮjinion to 

 which he had adverted that when VVarren showed the existence in 

 the Ostrich, Struthio Camelus, Linn., of a structure vvhich he re- 

 garded as an epiglottis, the denomination was generally rejected 

 even in this anomalous bird, and the part was considered as a mere 

 elevation at the base of the tongue, a rudiment, but without the 

 function, of the organ. In the Albatross, however, the function is 

 that of an epiglottis ; and the size, though small, is sufficient for the 

 protection of that portion of the rimą glottidis which cannot be • 

 closed in the manner usual in Birds by the apposition of its mar- 

 gins. With a peculiar structure of the glottis there exists an ap- 

 paratus equally peculiar in the class, as a provision against the in- 

 convenience which might otherwise result from the deviation from 

 the normai structure. 



Mr. F. D. Bennett also exhibited several specimens of a species 

 of Pyrosoma captured by him, on the 6th September 1832, at sea, 

 in lat. r 41' N., long. 11° 56' W. Between 2 and 4 a. m. the sea, 

 having been two hours before less luminous than usual, presented 

 one mass of bright phosphoric light extending to a considerable 

 distance around the vessel. The extensive field of bright luminous 

 matter emitted so powerful a light as to illuminate the sails, and to 

 permit a book of small print to be read with facility near the \vin- 

 dows of the stern cabins. Above this luminous field numerous sea 

 fowl were hovering in search of their prey. The light appeared to 

 be entirely owing to the Pyrosomata. 



Specimens taken from the sea and placed iu a vessel containing 

 sea water, ceased altogether to emit light, or emitted it but spa- 

 ringly while they remained at ręst. On the \vater, hovvever, being 



