SILICIOUS AND HORNY SPONGES WILSON. 419 



"be referred to the Phloeodictyinae. This is the opinion of Dendy 

 in his latest memoir (1921&, p. 45). 



Lundbeck, 1910 (pp. 28-29), again criticises the subfamily and be- 

 lieves the anatomical resemblances are features which have been 

 independently acquired, thus interpreting them as instances of con- 

 vergent evolution. Dendy in his recent memoir (19216) admits this 

 so far as to separate the non-cheliferous, haplosclerid, genera from 

 >Coelosphaera (=Histoderma) and its allies. 



Genus PHLOEODICTYON Carter (1882). 



Phloeodictyon Carter, 1S82, p. 122.— Lundbeck, 1902, p. 56. 



Rhizochalina part, Ridley, 18S4, p. 419. — Ridley and Dendy, 1887, p. 32. — 



Part, Topsent, 1894c, p. 6. 

 Oceana pia part, Dendy, 1894, p. 248. 



Spongin usually present, but the skeleton is not a reticulum of 

 •distinctly chalinine spiculo-fiber, as in Rhizochalina sens. str. Mega- 

 scleres, oxeas varying to strongyles, No microscleres. 



PHLOEODICTYON PUTRIDOSUM ( ?Lamarck. species). 



Rhizochalina putridosa ( ?Lamarck, species) Ridley and Dendy 18S7, p. 33. 



A fine large specimen from station D5355 is referable to this 

 species. It is spheroidal, 115 mm. in diameter. As in the Challenger 

 specimens the fistulae are numerous (about 40) and rise vertically 

 upward from the upper and lateral surfaces, facts which sufficiently 

 mark off the species from the more commonly recorded P. fistulosum 

 (Bowerbank), the original types of which came, like those of P. 

 putridosum, from Australian waters. In the Challenger specimens 

 the lower surface is ' almost without trace of fistulae'; in the Alba- 

 tross sponge it shows some small apertures, about 3 mm. in diame- 

 ter, which possibly indicate the presence in the uninjured sponge of 

 small root fistulae. In the Challenger specimens, 93-137 mm. in 

 diameter, the fistulae, 6-12 mm. in diameter, were nearly all broken 

 off close to the surface; unbroken ones short and closed terminally. 

 The fistulae in the Albatross sponge are of about same width; some 

 shorter ones perfect and terminally closed; most are broken off but 

 several are 60-70 mm. long although broken terminally. In the Chal- 

 lenger specimens the megascleres are oxeas, hastately pointed, 195 by 

 13 p; in the Albatross specimen they are similarly shaped oxeas, 

 but smaller, 150-160 by 8 \k. 



The Challenger specimens were much incrusted with foreign or- 

 ganisms. Likewise the surface of the Albatross specimen shows 

 some serpulid tubes, polyzoa, and molluscan shells. But the chief 

 incrustation is a calcareous (nullipore) alga (Corallinaceae). This 



