LANUGINELLA PUPA. Ö 



with the Lanuginella pupa examined by him. In fact, a case 

 of one and the same Hexactinellid species being firmly fixed when 

 growing on hard substratum but producing a root-tuft when living 

 on a soft bottom has never as yet been shown to exist. 



The general shape of the sponge is ovoid or sjiherical, usually 

 contracted below into a short stalk-like base. The bodv in laroer 

 specimens is often laterally compressed to a perceptible degree. 

 Its small size led Carter {'73 c/, p. 283 ; '73 b, p. 359) to 

 suspect that the species was based on young specimens of a larger 

 sponge. It seems the species never attains a large size, — a size 

 larger than, say, a large acorn or a hazelnut. One of the largest 

 specimens I have measured was ovoid in shape, measuring 19 

 mm. in height and 11 nun. by 14 mm. in breadth at the broadest 

 part. It had at the upper end a roundish osculum, o mm. in 

 diameter. AVall as thick as A2 mm. in the middle of the body. 

 Another large specimen, likewise ovoid in shape, measured 22 mm. 

 in length. 



The specimen shown in natural size in fig. 1, PI. I., measures 

 Kj mm. in height and 13 mm. bv 9 mm. in «-reatest breadth. 

 The osculum, 3 mm. in diameter. Thickness of wall, as much as 

 4 mm. — The specimens of figs. 2 and 3 measui-e respectively 17 

 mm. and 10 mm. in height. 



The osculum situated at or near the upper pole is always 

 comparatively small ; it is roundish or oval and has a thin smooth 

 edge, never supplied with marginal prostals. It leads into a 

 gastral cavity which is either pit-like or but slightly expanded 

 internally, on account of the considei-able thickness of the bodv- 

 wall in the middle. — F. E. Schulze found small young specimens 

 of 2-3 mm. diameter with the osculum still unopened. That 

 negative condition may sometimes, but certainly does not ahvavs, 



