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Show 532 DR. J. E. GRAY ON S P O N G E S . [May 9, When the two ends are equally developed they are equianchorate, when unequal inequianchorate, and the ends are distinguished as bidentate, tridentate, and palmate. Simple forms of spicula have the same shape from the beginning to the termination of their growth. Synopsis of sections of family. I. Defensive spicules unilateral, inequianchorate, attached to the skeleton. * Flukes entire, with central ridge (Genera nos. 1-4). ** Flukes palmate (Genus no. 5). II. Defensive spicules unilateral, bi- or tripolicated, free in the sarcode (Genera nos. 6 & 7). III. Defensive spicules unilateral, equianchorate, free in tbe sarcode. * Flukes divided into two or three spines at each end (Genera nos. 8-19). ** Flukes oblong, concave, with a central apical tubercle (Genus no. 20). *** Flukes cup-shaped, acute at each side (Genus no. 21). **** Spicules boat-shaped, with marginal sides (Genus no. 22). IV. Defensive spicules compressed, bihamate, booked at each end (Genus no. 23). V. Defensive spicules bihamate or contorted only (Genera nos. 24-30). VI. Defensive spicules regular, with rotate rays at each end (Genus no. 31). I. Defensive spicules unilateral, inequianchorate, attached to the skeleton. * Flukes entire, with a single central ridge, with a spine at its base. 1. ESPERIA, Nardo (part.), O. Schmidt, p. 54. Sponge branched, flexible, netted. Spicules of three kinds, united in the horny matter:-1. Pin-shaped. 2. Bihamate-that is, slender, cylindrical, bent up at each end, regular or tortose. 3. Equianchorate, minute; flukes ovate, with a central ridge ending in a spine below. ESPERIA TYPICA, Nardo. Esperia contavenii, O. Schmidt, p. 54, t. 5. f. 2 (pin-shaped spicules, double-headed, with a subbasal cross bar). B.M. Hab. Adriatic. |