414 - APPENDIX. 



mal. Camper found a membranous cist on the Reindeer above the thyroid 

 cartilage, and opening into the larynx, but I have met with no account of a 

 cist with a duct opening externally like that described by Mr. Hutchins, and, 

 unfortunately, I was not aware of his remarks until the means of ascertaining 

 whether such a sac exists in the Barren-ground Caribou were beyond my 

 reach." 



Mr. Morrow had several times looked for the cyst without success, but always 

 foro-ot to do so for the sac; and, in order to obtain some information on both 

 points, he went to the woods in December last, and succeeded in killing a large 

 buck, the result of the examination of which, and dissection of others, male 

 and female, made since, he would place before the Institute. But first, he 

 thought it necessary to give Camper's description of the membranous sac from 

 a Reindeer "four years old." Camper says,i " that as he did not know the 

 Reindeer, and as the imperfect account which Valentyn gave of Stenons's dis- 

 section in 1G72, did not give him much light, he was forced to proceed with 

 caution (date, June, 1771). He had often observed in the bucks, that when 

 these animals swallowed, all the larynx rose and fell in a peculiar manner, and 

 seemed to indicate something singular in this part. He then removed the skin 

 of the neck with much care. The muscles being raised in the same way, he 

 found a membranous sac, which had its origin between the os hyoides and the 

 thyroid cartilage. He then discovei-ed two muscles, which take their origin from 

 the lower part of the os hyoides, exactly where the base of the os graniform and 

 the cornua meet. These muscles were flat and thin at their beginning, but 

 widened towards their junction with the sac, and certainly served to support it 

 as well as to expel the air from it at the will of the animal. After he had opened 

 the oesophagus from behind, he found under the base of the epiglottis a large 

 orifice which admitted his finger very easily. This orifice spread, and formed 

 a membranous canal, which passed between the two muscles already men- 

 tioned, terminating in the membranous sac. Consequently the air driven from 

 the lungs into the larynx fell into this sac, and necessarily caused a consid- 

 erable swelling." 



Mr. Morrow said that when he shot t4ie buck alluded to, he had not seen the 

 account by Camper of the sac, and his specimen is not therefore so perfect as it 

 might otherwise have been. Examining the outside of the throat of the animal 

 the cyst of Mr. Hutchins, with " an opening through the skin," does not exist; 

 but immediately under the skin, there was a roundish sub-triangular cyst or 

 valve of cellular membrane of the " bigness of a crown piece," and on cutting 

 through the cellular membrane, this " valve " is found to be a closed sac hav- 

 ing a peculiar lining membrane, and closely packed with what may be called 

 loose hairs of a flaxen color, in a considerable quantity of sebaceous matter ; 

 at the same time, however, the lining membrane is covered by hairs of the same 

 quality growing from and rather lightly attached to it. Camper in his account 

 has described this valve as if it were the sac, and his drawing gives only the 

 valve, which the larynx exhibited by Mr. Morrow plainly shows. The muscles 

 which Camper describes as connecting the sac with the os hyoides, in Mr. 

 Morrow's specimen do not exist, but their representatives are probably the 

 muscles found in the larynx of the young buck by Dr. Sommers, as will later 

 appear. The valve is connected with the omo-hyoid muscles as they pass to- 



1 Camper, vol. i., chap, vi., page 338, Paris, 1803, where reference is made by let- 

 ters to a plate, which cannot be done here. 



