130 THE VOYAGE OF H.M.S. CHALLENGER. 



felt iu the dried condition like a delicate woollen cocoon, and he added the specific name 

 pupa on account of the shape already noted. 



Only one species is known, Lanuginella pupa, 0. Schmidt. 



Lanuginella pupa, 0. Schmidt (PL LIII. figs. 3-5). 



In the vessels which contained the spirit specimens collected at Station 192, off Little 

 Kj Island, I found, along with the large Pheronema gigantewn and several specimens of 

 Polylophus philippinensis, a number of oval and spherical structures 2 to 8 cm. in 

 diameter, which turned out on closer inspection to be small sponges. Some of them 

 were seen to be representatives of the Lanuginella pupa described by Oscar Schmidt,' 

 while the others were young forms of Poli/lophus j)ltilipi'>inensis which will be again 

 referred to in the description of that form. 



Lanuginella pupa, which occasionally grows on other Hexactinellida, has the form 

 either of a completely closed smooth sphere, 2 to 3 mm. in diameter, or of a larger oval 

 body with a somewhat flattened basal pole, and a round oscular opening about 1 mm. in 

 breadth at the narrow upper end {PI. LIII. fig. 3a, b, 4, 5). 



On a longitudinal section of the larger ovoid specimen, one observes the central 

 longitudinal gastral ca-vdty, which is rounded off at the lower end, opening superiorly of 

 course in the already mentioned osculum. Into this gastral cavity, which is Lined by 

 a subgastral trabecular network, the sack-like chambers open, either directly, or by 

 means of canal-like efferent passages, and in this case the whole chamber layer is deeply 

 folded. Between the smooth external network or dermal membrane and the folded 

 chamber layer, there is an external or subdermal trabecular space, including a subdermal 

 trabecular network and the subdermal sj)aces or afferent canals which penetrate tlie latter 

 (PL LIII. fig. 5). 



The parenchyma of the sponge contains, as 0. Schmidt noted, medium sized oxyhexacts 

 with long straight or slightly curved rays usually disposed radiaUy and tangentially. 

 Besides these principal forms,, somewhat long, straight, or slightly curved oxydiacts occur, 

 with a central axial cross, over which cruciate tubercles often project outwards as indications 

 of the undeveloped rays. The disposition of these oxydiacts, which are often somewhat 

 roughened terminally, is for the most part perfectly or approximately tangential, though, 

 in some cases, it may be more or less divergent (PL LIII. fig. 5). 



Between these large supporting spicules, we have to note the ii-regular scattered 

 occurrence of small regadar oxyhexacts with thin rays, and of numerous small disco- 

 hexasters, in which each of the short, simple, cylindrical princijmls bears three, four, or 

 five long diverging terminal rays with four to six-toothed, somewhat recurved, transverse 

 discs at their extremities (PL LIV. fig. 3; PL LIII. fig. 5). Besides these, the 



1 Grundziige einer Spongienfauna ties atlant. Gebietes, p. 13. 



