Genus 5. TROCHOSPONGILLA, Vejdovsky (1883). 18. _T. latouchiana_*, Annandale (1907). 19. _T. phillottiana_*, Annandale (1907). 20. _T. pennsylvanica_* (Potts) (1882). Genus 6. TUBELLA, Carter (1881). 21. _T. vesparioides_*, Annandale (1908). Genus 7. CORVOSPONGILLA, nov. 22. _C. burmanica_* (Kirkpatrick) (1908). 23. _C. lapidosa_* (Annandale) (1908). Order HALICHONDRINA. Siliceous monaxon sponges in which the horny skeleton is much reduced or absent and the spicular skeleton is more or less definitely reticulate. The microscleres are usually rod-like and rarely have more than one main axis. Family SPONGILLIDÆ. SPONGILLADÆ, J. E. Gray, P. Zool. Soc. London, 1867, p. 550. Freshwater Halichondrina which at certain seasons produce gemmules armed with peculiar microscleres. Two distinct kinds of microsclere are often present, that associated with the gemmule sometimes consisting of a vertical shaft at the ends of which transverse disks or rotulæ are borne. There is always at least a trace of a subdermal cavity. Many authors divide the Spongillidæ into two subfamilies:--Spongillinæ (or Euspongillinæ), in which the gemmule-spicules have no transverse rotulæ, and Meyeninæ (or Ephydatiinæ), in which they have rotules at one or both ends. So gradual, however, is the transition that I find it difficult to decide in one instance to which of two genera, typical respectively of the two "subfamilies," a species should be assigned. Minchin in his account of the Porifera in Lankester's "Treatise on Zoology" (1900) regards the Spongillidæ merely as a subfamily of the Heterorrhaphidæ, and there certainly are few differences of a definite nature between them and the marine family (or subfamily) Remeridæ. _Key to the Indian Genera of_ Spongillidæ. I. Microscleres without transverse disks. A. Microscleres of the parenchyma similar in general structure to those or the gemmule; the latter without comb-like vertical rows of spines at the ends SPONGILLA, p. 67. B. Microscleres of the gemmule with comb-like vertical rows of spines at both ends PECTISPONGILLA, p. 106.