Sjionges frotn Funafuti. 357 



Several small, massivr, ainl <lii;itate spociiueiis of this 

 spoiif^c occur t'mm depths of 2o-8() fathoms, either as dried 

 washed-out skeletous or preserved in fonnaiiu ; the branches 

 of one of the digitate varieties anastomose. The dermal 

 membrane is dark .slate or black and the interior rich yellow. 



Localit'KS. Funanuua, 2o-4.j fath. ; Falefatu, <S0 fath.; 

 and Funafuti Islet. 



]>istrihitlion. Api, New Hebrides, 60-70 fath.; Tahiti, 

 reefs ; Funafuti Atoll. 



Luffariella qeometrica, sp. n. 



(PI. XV. ti-r. 1,«-C.) 



Sponge forming two subspherical masses attached to a 

 branch of Seridtopora, the larger being 20 millim. in diameter. 

 Colour reddish brown ; consistence soft and elastic. 



The dermal membrane sandy in parts, but in other parts 

 transparent, the whole sponge being more or less transparent 

 and allowing one or more concentric spheres (indicating 

 periods of growth) to be visible in the interior. Oscules level 

 with the surface and G millim. in diameter. 



Surface conuli 210 yu., formed by projecting main fibres. 



Skeleton forming a regular rectangular network composed 

 of radiating primary main fibres, joined by secondary hori- 

 zontal fibres in such a manner as to form triangular shatts ; 

 tertiary fibres also j)resent, more or less irregularly distributed. 



Dermal skeleton a legular reticulum in which usually six 

 secondary fibres radiate out from each nodal vertical primary 

 fibre, the joined bases of the resulting triangles forming more 

 or less regular hexagons; the primary meshes filled in with 

 a network of more slender fibres. 



Fibres. — Primary main fibres 17r)-210 /x, secondary llO/x, 

 tertiary 1<5 fj,. 



Width of meshes about 700-1500 /a in width and 400-650 /a 

 in height. 



Flagellated chambers subspherical, 32 /x m diameter. 



The present form constitutes the fifth described species of 

 the genus. L. geometrica is more nearly allied to L. calyx, 

 Leiidenfeld, from the Indian Ocean, than to the other species, 

 but differs from it in biing devoid of gyriform protuberances 

 on the surface. 



I'he pith of the fibres occu|)ies about one third of their 

 diameter and is clearly dift'erentiated by staining with borax 

 carmine. 



Lucality. W. of Tutanga, 30 fath. 



