TETRAXONIDA 



283 



Haltclotia, devoid of special dermal skeleton and with the primary fibres of the main 

 skeleton continued outwards beyond the ectosome. Sections of the sponge, taken at 



ilJMJJL 



/I 



\^1 



a b 



Fig. 17. Callyspongia flabellata, sp.n. a, section at right angles to surface, x 60; 

 b, dermal skeleton, x 60; c, oxeote, x 400. 



right angles to the surface, show, however, even to the naked eye, that there is a definite 

 and unmistakable dermal skeleton. This is the more readily apparent since the interior 

 of the sponge is cavernous and the ectosome compact and firm. 

 The species is characterized mainly by its external form. 



Genus Phloeodictyon, Carter 



Phloeodictyon eumitum, Kirkpatrick. 



P. eumatum {sic), Kirkpatrick, 1903, p. 253, pi. v, fig. 18, pi. vi, fig. 19 (the name is spelt 

 eumitum on p. 235, and in the explanation to the plates). 



Occurrence. St. 6: Tristan da Cunha, 80-140 m. 



Distribution. Natal. 



Family DESMACIDONIDAE 



Section ISODICTYEAE 



Genus Isodictya, Bowerbank 



Isodictya kerguelensis (Ridley and Dendy). 



Homoeodictya kerguelensis, Ridley and Dendy, 1886, p. 2^6; id., 1887, p. no, pi. xxiii, fig. 3, 

 pi. xxiv, fig. 3; Desmacidon kerguelensis, Topsent, 1908, p. 24; Homoeodictya kerguelensis, id., 

 1917, p. 67. 



Occurrence. St. WS 79; Falkland Islands, 131-132 m. 



Distribution. Kerguelen; Graham Land. 



