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XXIV.—On the Structure and Arrangement of the Soft Parts in‘Euplectella 
aspergillum. By Professor FRANz EILHARD ScHULZE, Graz. Communicated 
by Sir WyviLte Tuomson, V.P.R.S.E. (Plate XVII.) 
(Published by permission of the Lords Commissioners of the Treasury. ) 
Although, from the careful descriptions which have been given by several 
competent naturalists, we may now consider ourselves tolerably well acquainted 
with the structure of the dainty siliceous skeletons of this and several allied 
Hexactinellid Sponges, this is by no means the case with their soft tissues ; 
and the great cause of our imperfect knowledge of these interesting structures 
is that no observer has hitherto succeeded in procuring a really well-preserved 
Sponge of this group. It was with pleasure, therefore, that I accepted the 
offer of the Director of the Challenger Expedition to place some well-preserved 
examples belonging to different genera in my hands for investigation. Of all 
the specimens which have been sent to me, some fragments of Huplectella 
aspergillum in absolute alcohol are much the best preserved, and therefore the 
best suited for thorough examination. I commence with the description of the 
soft parts of this well-known and beautiful form, following the classification 
which has been adopted by Sir WyviLLE TuHomson in his descriptions of the 
species. 
1. ON THE Sort Parts or Euplectella aspergillum (R. OWEN). 
I received in January 1880, from the Challenger Office in Edinburgh, an 
entire specimen of Luplectella aspergillum preserved with its soft parts in 
methylated spirit, and six bottles containing fragments of the same species 
preserved according to different methods, viz. :— 
1. In picric acid. 
2, In solution of acetate of potash, after previous treatment with osmic acid. 
3. In chromic acid. 
4. In glycerine, after previous treatment with nitrate of silver. 
5. In absolute alcohol, after previous colouring with carmine. 
6. In absolute alcohol simply. 
I will commence with a short abstract of previous communications on the 
subject by other naturalists. 
In 1868, after examination of dried fragments, Sir WyviLLe THomMson 
characterised the soft parts of the Hexactinellide, which he supposed to be 
VOL. XXIX. PART II. 7U 
