. Guide leaflet. network. Sometimes the whole colony assumes an erectvase-like form with walls made up of entwining tube-like in-dividuals. The sponge on exhibition is of the encrusting type,growing in this instance on a colony of barnacles. The Sycon sponge, Grantia ciliata Fleming, represents in theexhibition the order Heterocoelida. This is a common speciesfound all along the New England sea-coast. It is a small tubularsac with the osculum surrounded by a circle of finger-like spicules,as shown in the illustration on page 224. It grows from an inchto an inch and a half in length, in small c
. Guide leaflet. network. Sometimes the whole colony assumes an erectvase-like form with walls made up of entwining tube-like in-dividuals. The sponge on exhibition is of the encrusting type,growing in this instance on a colony of barnacles. The Sycon sponge, Grantia ciliata Fleming, represents in theexhibition the order Heterocoelida. This is a common speciesfound all along the New England sea-coast. It is a small tubularsac with the osculum surrounded by a circle of finger-like spicules,as shown in the illustration on page 224. It grows from an inchto an inch and a half in length, in small cluster-like coloniesattached to sea-weed, submerged timbers, shells, etc. Thespecimens in the glass jar are growing on a mussel shell whichis also partly encrusted with small star-shaped colonies of theinteresting Ascidian, Botryllus. B. THE NON-CALCAREOUS SPONGES (CLASS NON-CALCAREA). The sponges of this class have no traces of carbonate of limein their skeletons. Instead some contain silicious spicules[24] 238. FIQ. 18-—A RARE GLASS SPONGE {HyuUuciU timili* Ijima)This graceful specimen illustrates the vase-like growth of many sponge colonies (Height, 15 inches. |[25r 239 24o THE AMERICAN MUSEUM JOURNAL (the so-called glass sponges), or their skeletons may be partlyor entirely made up of a network of spongin fibers. A fewspongesJiave no skeletons at all. Those sponges which have six-rayed spicules belong to theorder Hexactinellida, a group marked by forms of unusual beautyand grace, of which a fine collection is shown in this alcove. Insome of these (suborder Lissacina), the spicules are independentduring growth and are felted together by means of their hooksand spines; in others (suborder Dictyonina), the overlappingends of the spicules have grown together to form a rigid lattice-like framework. Suborder Lissacina.—The several species of Euplectella(Venuss Flower-basket) are especially noticeable for delicatebeauty, while Walteria is remarkable for its odd tree-like form.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectnatural, bookyear1901
