. Chambers's encyclopedia; a dictionary of universal knowledge for the people. f Leidy are types of peculiarly Americanfamilies. P. mngnifiea is a large species, with aglobular gelatinous basis, nearly a foot in diameter. Minute appendages, of a very remarkable char-acter, are fixed to the cells of many of the are termed Avictdaria, or Pirds-head Pro-cesses, and Vibracula, orwhip-like spines. TheAvicuktria were describedby Ellis, who first noticedthem (in his Essay towardsa Natural History of theCorallines, 175S), as resem-bling a birds head witha crooked beak, openingvery wide; t
. Chambers's encyclopedia; a dictionary of universal knowledge for the people. f Leidy are types of peculiarly Americanfamilies. P. mngnifiea is a large species, with aglobular gelatinous basis, nearly a foot in diameter. Minute appendages, of a very remarkable char-acter, are fixed to the cells of many of the are termed Avictdaria, or Pirds-head Pro-cesses, and Vibracula, orwhip-like spines. TheAvicuktria were describedby Ellis, who first noticedthem (in his Essay towardsa Natural History of theCorallines, 175S), as resem-bling a birds head witha crooked beak, openingvery wide; they consistof a fixed and a movablenip])er, like a crabs claw,the latter being worked bysjiecial muscles. Thesemoving beaks have beenoften observed to seizeminute animals; but as•jN^v^ these organs have no powerof passing their prey tothe mouth, the P. cannotreceive nourishment fromthis source. Mr (iosseingeniously suggests that the seizure oif a passinganimal, and the holding ofit in the tenacious graspuntn it dies, may be ameans of attracting theproper prey to the vici-. nity of the mouth. Theand by the covering of the mouth of the cell. The I vibracula consist of a long, slender movable seta oranimal may either expand itself to a considerable bristle, which, according to Gosse, serves to ridextent out of the mouth of the cell, or it uuiy be j the animal of intruding vagrants, and to cleanse 661 —POMBAL. ftway accidental defilement, by sweeping across theoritice of the cell. Both these kinds of organs areof service in determining genera. Excellent magni-fied representations of the Avicularia and Vibraculamay be seen on referring to figs. 13 and 11, in MrBusks excellent article, Polyzoa, in The EngllihCiidopirdia, to which, as also to that gentlemansCatalogue of Manne Polyzoa in the British Museum,and to Professor Allmans Report on the Fresh-water Polyzoa, published in the Reports of theBritish Association for 1851), the reader is referredfor further information re
Size: 1347px × 1854px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, bookpublisherphiladelphiajblipp
