A NEW FIELD FOR THE MICROSCOPIST. 
131 
Fig. 36. Sporocyst of a species of Halichonclria bursting and liberating its 
contained spores. 
„ 37. Sporocyst and liberated spores of another siliceous sponge. 
„ 38. F ragment of the cavity-lining of Gastrophysema dithalamium (Haeckel) , 
one of the simplest known sponge forms ; showing two collar-bear- 
ing monads, two larval or amoeboid cytoblasts, and a flask-shaped 
sporocyst, copied from Prof. Haeckel's illustrations of the species. 
PLATE IV. 
Fig. 1. Adult colony-form of Polynceca dichotoma , S. K. 
„ 2. Colony of numerous individuals of Solpingceca amphoridium , J. Clk., 
attached to a confervoid filament. 
„ 3. A single individual of the same species in its normal and fully ex- 
panded state. 
„ 4. Monad with collar withdrawn but flagellum remaining, and pro- 
truding a portion of its body-sarcode from the orifice of its lorica. 
„ 5. Monad with collar and flagellum withdrawn, and the body-sarcode 
protruded as lobate pseudopodic processes. 
,, 6. The protruded portion of the above detached in the form of a 
minute stellate amoeba. 
„ 7. The quiescent or encysted condition of the same species. 
„ 8. Solpingceca inquillata, S. K., larval form in the act of constructing 
its lorica. 
„ 9. Adult individual of the same species. 
„ 10. An individual of the same species multiplying by transverse fission. 
,, 11. Solpingceca, ampulla , S. K. 
„ 12. Deserted lorica of the same species exhibiting fluted markings. 
„ 13. An early phase of the same species in which the lorica is as yet only 
in a mucilaginous condition ; the uniflagellate monad, marked a, 
adherent to the top left-hand corner of this sheath, is a larval form 
of the same species. 
„ 14. The same larval form represented at 13a, commencing the construc- 
tion of its lorica by a process of exudation. 
„ 15. Solpingceca cylindrical S. K. 
„ 16. Sociable colony of Solpingceca tuba , S. K. 
,, 17. Two monads of Solpingceca gracilis, J. Oik. 
18. Solpingceca cornuta, S. K., the monad adherent to its lorica pos- 
teriorly by three pseudopodic prolongations. 
„ 19. Another monad of the same species adherent to its lorica by a single 
and elastic pedicelliform extension of its body substance. 
„ 20. An individual of Solpingceca gracilis, J. Clk., dividing into two by 
transverse fission ; at a the separated anterior half swimming off 
as a simple uniflagellate monad. 
„ 21. Two individuals of Solpingceca longipes, S. K. 
,, 22. Empty lorica of Solpingceca teres, S. K. 
„ 23. Solpingceca fusiformis, S. K., in its normal and fully expanded state. 
„ 24-26. Three developmental conditions of the same species illustrating 
respectively the amoeboid, encysted, and sporuliferous phases. 
