146 



THE SPONGES. 



character of the bipocillus cannot be regarded as a feature indicative in 

 itself of species-relationship, since in the very different Iophon lamella, 



the bipocilli are also chelate. 



chelift 



Canada (1893, p. 30), and from several localities off the Atlantic coast 

 of Canada (1896, p. 191 ; 1900, p. 23). Lambe's specimens differ in hab- 

 itus from mine, being " amorphous and honeycombed," or massive, per- 

 forate, and consisting " of an inosculation of short, stout, irregularly shaped, 

 nodose branches, which coalesce, frequently to such an extent as to become 

 amorphous " (1893, p. 30). 





Iophon lamella, sp. nov. 



Plate 20, Figs. 3, 7-9, 13, 13. Plate 24, Figs. 3-4. 



Diagnosis. Body lamelliform, 5 to 12 mm. thick. Efferent canals, 1-2 mm. in diameter, 

 open in abundance over both surfaces. The surfaces, upper and lower, are in a measure 

 differentiated. Pores irregularly scattered throughout the dermal membrane, wherever it 

 overlies the skeletal reticulum. Spicules. 1. Spinose style, 210-220 /* x 12-16 /x. 2. 

 Tylote, 220-240 /x x 7-8 /*, ends minutely spinose. 3. Chelate bipocillus, 12-16 p long ; 

 terminating at small end in two pointed teeth, at larger end in a bilobed plate. 4. Ani- 

 sochela, 14-28 p long, palmate. Main skeleton a uniform reticulum of spinose styles. 

 Meshes commonly triangular. Side of mesh formed by 1, 2, 3, or occasionally more 

 spicules. 



Station SJfOS, five specimens. 



The sponge body is lamellar but irregularly thickened, and sometimes 

 considerably curved ; the free edge not possessing special characters dis- 

 tinguishing it from the rest of the surface. The thickness varies from 5 

 to 12 mm. ; greatest width, about 50 mm. The sponge is firm, and while 

 easily broken is not especially brittle. The color is a light yellowish-brown. 

 The upper surface of a specimen is shown in Fig. 12, Plate 20, and the 

 lower surface of the same specimen in Fig. 13, Plate 20. 



The surfaces of the plate-like body are in a measure differentiated. 

 The one surface, designated as the upper, is more even and in general of 

 a lighter color. The other surface, regarded as the lower, exhibits shallow, 

 irregular, and large concavities, as if here moulded over an underlying 



object. 



The appearance of the surface is extremely variable, although there 

 is an underlying uniformity of character. This appearance is largely 



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