270 PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



demi-canal, paved in the same way with cells as the chambers them- 

 selves. 



Not seeing the sponge in an absolntely fresh condition, I conld not 

 observe the action of the funnels in life; but once while the whole sponge 

 was still in a comparatively fresh condition, and under observation in a 

 zoophyte trough, I saw one of the inverted funnels suddenly everted and 

 expanded to apparently its fullest extent. I was also unable to detect 

 the slightest evidence of any other kinds of openings besides the funnels 

 into the organism, and these were of about the same size throughout. 

 This fact, together with others which I ha^^^e stated, removes all doubt 

 as to the sponge nature of the organism. 



There is no form known to me in literature which corresponds to this 

 in structure. Halisarca does not have a tough membranous ectoderm, 

 while the Physemaria have an ecto-skeleton, composed of the shells of 

 Foramimfera. But as the existence of the Physemaria has been apx)ar- 

 ently doubted by some zoologists, the position of Camaraphysema becomes 

 an interesting question. At any rate it may be safely placed close to 

 the fleshy sponges, and may possibly constitute a distinct family. 



The account now offered, while it is not as complete as might be de- 

 sired, rests upon sufficient evidence to make it desirable that the fullest 

 possible descrii)tion of the organism should be put uj^on record for the 

 benefit of those who may have the opportunity of extending or confirm • 

 ing my interpretation of its anatomical and embryological features. 

 While I could hardly convince myself at first that I did not have before 

 me some one of those curious compound Ascidians of the suborder 

 Synascidm, the absence, however, of a common cloacal cavity and any 

 indications of a branchial apparatus or a digestive canal satisfied me 

 that I was not dealing with a tunicate, but that I should have to look 

 among the very lowest of the sponges for its nearest affines. 



I have stated that no collar or flagellum could be detected as forming 

 the inner extremities of the cells lining the cavities. This fact does 

 not, however, render it improbable that such structures exist in the liv- 

 ing animal, as it must be borne in mind that both Bowerbank and Carter 

 have called attention to the circumstance that the flagellate cells of 

 sponges withdraw their collars and flagella after death. The extreme 

 iittitability of sponges is notorious, and to one who sees it for the first 

 time would be considered remarkable, audit is not unlikely that Cama- 

 raphysema partakes of this characteristic, known to be well-nigh common 

 to all the members of the group. 



The exact locality from whence this species was derived could not be 

 ascertained ; all that the writer could learn was that the lot of oysters 

 from whence he had obtained his specimen had certainly been brought 

 from the waters of the Chesapeake. It is to be hoped that more speci- 

 mens will be brought to light, as the writer in investigating his unique 

 specimen was obliged to sacrifice it in order to make, his study as com- 

 plete as possible by slicing it up into sections. 



