. Cassell's natural history. Animals; Animal behavior. THE LARGBST INFUSORIA. 307 t U-' // Hg. 21. — BVHSARIA TRUNCATELLA. (Afier Stein.) Fig. 22.—SPIROSTOMUM AMBIGtUM. (Aflcr SU\ and in two long rows. These animalcules increase by several divisions across the body, and their length is ^.'^th of an inch. .SUB-ORDER HETEROTRICIIA. These Ciliata are free swinnning or attached, naked or loricate, and the cilia form two witlely distinct systems; those of the general surface being short, and those of the oral region large and like cirrL These oral cilia are either linear in their arrangement, or fo
. Cassell's natural history. Animals; Animal behavior. THE LARGBST INFUSORIA. 307 t U-' // Hg. 21. — BVHSARIA TRUNCATELLA. (Afier Stein.) Fig. 22.—SPIROSTOMUM AMBIGtUM. (Aflcr SU\ and in two long rows. These animalcules increase by several divisions across the body, and their length is ^.'^th of an inch. .SUB-ORDER HETEROTRICIIA. These Ciliata are free swinnning or attached, naked or loricate, and the cilia form two witlely distinct systems; those of the general surface being short, and those of the oral region large and like cirrL These oral cilia are either linear in their arrangement, or form more or less spiral or circular series. The cortical layers are well developed, and some- _^ ^ .^ times contain parallel muscular tibrilhe. /1 , ' \ The largest Infusoria are amongst this sub-order, which may be divided into /' '1 a family, the Bursariadse (Fig. 21), which has the cilia near the mouth confined to • ^'^ the left border of the mouth groove, and into six other families which have the mouth cilia in a spiral or circidar series round the aperture. The first family of this second gi'oup has free-swimming animalcules, and the fringe of cilia around the oral aperture is confined to the ventral surface, and the anal orifice is behind and at the end. Sjnrostomum ambiyimm is the type of the family, and is one of the largest animalcules, measuring ^th to ^th of an inch in length, ajid being visible to the nakotl eye, "gleaming," Saville Kent remarks, " like golden threads in the sunlight " (Fig. 22). When they are placed in clean water off the duckweed on which they like to move, the body is long and filiform, has a tendency to twist itself and untwist, and the eye is stnick by the long contractile vesicle which occupies much of the hinder part of the body, and by the endoplast, which is long and •:."'^'°^' '^fei^''" moniliform. The slit for the mouth is __;^/^^ surrounded by cilia. ^^^^^^ Another member of the family is Condylosto
Size: 1474px × 1696px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjecta, booksubjectanimals
