Comprehensive DescriptionRead full entry
“Myxilla basimucronata, sp.n. (Fig. 26).
Holotype. B.M. 220.127.116.112.
Occurrence. St. 42: South Georgia, 120-204 m.; St. WS27: South Georgia, 106-109 m.; St. WS42: South Georgia, 198 m.
Diagnosis. Sponge of small size, sub-ramose with cylindrical branches or forming dorso-ventrally flattened lobes; surface smooth, even; dermal membrane readily separable; sub-dermal cavities spacious; pores and oscules not apparent; colour, in spirit, pale brown; main skeleton a regular reticulation of smooth styli, 0.47 by 0.017 mm.. slightly curved and bearing a basal mucron; dermal skeleton a tangential layer of tornota regularly crossing each other in all directions, supported by brushes of tornota planted directly on distal ends of ascending fibres of main skeleton; tornota inequiended, 0.25 by 0.008 mm., with ends slightly swollen and bearing a terminal mucron surrounded by numerous microspines ; microscleres sigmata of two sizes, 0.042 and 0.025 mm. chord, and ancorae spatuliferae of two sizes, 0.042 and 0.021 mm. chord.
Remarks. The species is very closely related to M. magna, Topsent, and it is indeed possible that the two may eventually prove to be identical, but the present species differs from Topsent's species in external form, in the dimensions of its spicules and in the presence of a basal mucron on the styli.”