SPONGIARIA 75 



Key to the classes of Spongiaria: 



o x Small marine sponges with calcareous spicules and large collar cells and 



mostly under 2 cm. in length 1. CALCAEEA 



o 2 Usually larger sponges with silicious spicules or spongin fibres, or both, or 

 without either. 



&! Glass sponges ; spicules usually six-rayed 2. HEXACTINELLIDA 



6 2 Massive sponges without six-rayed spicules ; skeleton of silicious spicules, 

 spongin or both, or wanting 3. DEMOSPONGIAE 



CLASS 1. CALCAREA.* 



Marine sponges of small size with 1-rayed, 3-rayed or 4-rayed cal- 

 careous spicules; most of them are cylindrical in shape, colorless, either 

 solitary or colonial, and live in shallow water: 2 orders with about 150 

 species. 



Key to the orders of Calcarea: 

 Oi Body wall thin and porous ; central cavity lined with collar cells. 



1. HOMOCCELA 



Oo Body wall not thin ; central cavity without collar cells 2. HETEROCCELA 



ORDER 1. HOMOCCELA. 



Very simple, thin-walled sponges in which the central cavity con- 

 tains the collar cells; each pore in the body wall is a perforation of a 

 single thickened dermal cell leading into the cavity : 2 families and over 

 50 species. 



FAMILY LEUCOSOLENIIDAE. 



With the characters given above; no radial canals or flagellate 

 chambers; with straight, triradiate, or quadriradiate spicules: 4 genera. 



1. LEUCOSOLENIA Bowerbank. Usually 

 colonial, although sometimes simple 

 sponges, consisting of a mass of narrow 

 anastomosing tubes: numerous species. 



L. botryoides Bow. (Fig. 135). Sponge 

 up to 35 mm. long, ivory white in color, and 

 consisting of a mass of slender tubes; 

 spicules 1 and 3-rayed and faint yellow in 

 color: in shallow water; Martha's Vine- 

 yard to Gulf of St. Lawrence; Europe. Fi s- 13 5 



L. cancellata Verrill. Sponge massive, 



consisting of small anastomosing tubes, up to 3 cm. in length and yel- 

 lowish in color: walls thin, with triradiate and quadriradiate spicules: 

 Casco Bay to Arctic Ocean. 



* See "Die Kalkschwamme," by E. Haeckel, 1872. 



