26 R. KIRKPATRICK. 



At the base of the spines is the thin dermal membrane, generally torn away, thus 

 exposing the circular openings of inhalant channels. 



The new species comes well within the genus Ophlitaspongia Bk., as amended by 

 Dendy (5. p. 36). 0. seriata Bk., 0. subhispida Carter, and 0. membranacea 

 Thiele, all have toxa, but the first and third species are encrusting, and the second has 

 long slender branches. The chief characters of the new species are the strongly spined 

 surface, and the great development of the spicular core, the spongin not being so 

 abundant as in other species, and not forming distinct fibres. 



The single specimen was dredged off Coulman Island in 100 fms. 



LISSOMYXILLA Hanitsch. 



This genus was established by Hanitsch (8. p. 194), to include Ectyonine Sponges 

 with fibres having a core of smooth styles echinated by acanthostyles and with special 

 ectosomal megascleres ; with or without microscleres. Unfortunately the species he 

 selected as type of the genus ( Tethea spinosa, Bowerbank) in no way fell in with the 

 definition, since, as Topsent points out (28. p. 265), this species has neither echinating 

 spicules nor special ectosomal spicules, and Topsent refers Lissomyxilla to the limbo of 

 useless names. Among the ' Discovery ' sponges, however, is a specimen which fits in 

 with Hanitsch's definition of Lissomyxilla, which runs, " Skeleton fibres of the 

 choanosome, formed of smooth monactinals echinated by spined styles. Megascleres of 

 the ectosome smooth diactinals or monactinals. Microscleres (isochelae, &c.) may be 

 present." Accordingly, I propose to revive the name. 



LISSOMYXILLA HANITSCHI. 



(Plate XXII., fig. 7, and Plate XXVI., fig. 4a-c'.) 

 1907. Lissomyxilla hanitschi Kirkpatrick (10a. p. 275). 



Description. There are two much-worn pieces of this sponge of a dark, dirty-gray 

 colour, and a third young small specimen, whitish in colour, growing on a specimen of 

 Hornera. The largest specimen is 4 cm. high and 5 cm. in diameter at the base ; the 

 dermal membrane is worn away, exposing several openings of exhalant canals, 4 mm. in 

 diameter. The dermal membrane of the smallest specimen is transparent, smooth, 

 and raised up at one place into a small conical oscule, with radial tangential spicules in 

 its walls. 



The skeleton of the choanosome is formed of branching fibres on an average 

 about 150/a thick, echinated by spined styles in an obscurely verticillate manner, the 

 whole skeleton, as seen in sections, having a somewhat confused appearance. The 

 ectosomal spicules partly proceed obliquely from the main fibres to the dermal 

 membrane, and partly lie tangentially in that membrane. 



Spicules. Megascleres. Smooth styles, 500 X 19/i, smooth, curved near the 

 head, sharp-pointed. 



