212 PORIFERA. II. 



1880. Melonanchora elliptica O. Schmidt, Spong. des Meerbus. von Mexico, II, 85, Taf. IX, Fig. 8 A— F. 



1887. — Fristedt, Vega Exp. vetensk. Iakttag. IV, 454, PI. 25, figs. 51 — 55. 



1892. — — Herdman, Trans. Liverp. Biol. Soc. VI, 85. 



1892. — Topsent, Resultats des Camp, scient. du Prince de Monaco, Fasc. II, 101. 



1903. — — Arnesen, Spong. von der norweg. Kiiste, Berg. Mus. Aarb. 1903, No. 1, 17, 



Taf. II, Fig. 4, Taf. V, Fig. 4. 



1904. — Topsent, 1. c. Fasc. XXV, 177, PI. IV, fig. 10. 



Massive, sometimes somewhat roundlobed. The surface closely set zvith higher or lower, zuart- 

 shapcd pore papilla', otherivisc smooth. The dermal membrane hyaline, very solid, with close-lying, hori- 

 zontal dermal spicules, supported by fibres of dermal spicules. Oscula spout-shaped , few , scattered 

 between the pore papilla'. The skeleton an irregular , chiefly polyspicular network of fibres passing 

 towards the surface, and between them scattered spicules and spicula-bundles. Spicula: Alegasclera: the 

 skeletal spicules styli, often with, rounded point, o-68 — o-86'" m , the dermal spicules tylota to strongyla 

 0-4.1 — 0-62"""; microsclera of three forms, spha'rancora; 0-054 — 0-068""", ancora; spatuliferat of two forms, 

 large ones 0-047 — o-o?y'"", small ones 0-021 — 0-028""". 



This species is of a massive form; the smaller specimens are more or less ronudish, the larger 

 ones may be more expanded and somewhat roundlobed. The species has a very characteristic exterior, 

 being rather closely set with wart-shaped papillae of a peculiar structure, which will be more parti- 

 cularly described below. The specimens in hand which are not torn off from the substratum, are 

 attached to stones and shells. The largest specimen, which is of an irregular, massive form, but is 

 no entire one, has a greatest extent of ca. ioo mm and a greatest thickness of 55 mm . This specimen 

 shows three flat, round eminences or lobes (PI. VII, fig. 4). Another, tolerably entire specimen is higher 

 and more lump-shaped, it has a height of ca. 65 mm and a similar breadth. The smallest specimen is 

 irregularly roundish, of a diameter of ca. 25""". The colour (in spirit) is whitish or yellowish white. 

 The skin is firm and solid, but the consistency of the inner body is rather brittle. The stirfacc is 

 smooth without projecting spicules. The dermal membrane is a hyaline, very solid, and easily separable 

 membrane, provided with close-lying spicules. Oscula and pores: As mentioned above, the surface is 

 set with close-standing papillae ; these papillae, in their fully developed state, are formed as high warts, 

 being cylindric and with rounded ends. They are not rarely broadest in their upper part, and the 

 part below is narrowed somewhat like a neck. In their fully developed state they have generally a 

 height of 4 — 5 mm , and a breadth above of 3 — 4 mm ; in some specimens, however, they may be somewhat 

 larger. These papillae, which are supported by a network of spicules, have pores in the meshes of 

 the net. The pores are close-standing, so that the membrane, which is here thin and transparent, 

 becomes a sieve; they are round or a little oval, and their diameter was measured to 0-037 — o - i8 mm . The 

 pores are not only found in the upper part of the papillae, but also down on their sides. The close 

 spiculation of the dermal membrane ceases at the base of the papillae, and from this point polyspicular 

 fibres issue passing up into the wall of the papilla and forming a net of meshes, the single meshes 

 of which may again be subdivided by thinner fibres or single spicules. In these meshes the pores 

 are situated. This description holds good of the papillae, when they are fully developed. Besides 



