794 THE ANIMAL KINGDOM. 



channels, and the surface of the sponge is smooth, Uteinae ; and with the 

 same coalescence the cones themselves may become branched, Grantinae^-. 

 Two sets of pores are to be distinguished in consequence of the establish- 

 ment of the branched inhalent set of canals : the pores at the surface 

 of the sponge, and the. pores by which the canals open into the cones. 

 A transition to the next type is indicated in the Uteine Amphoriscus 

 elongatus, where a certain number of cones may have a common aperture 

 into the oscular tube. (3) The collared flagellate endoderm is confined 

 to sac-like chambers or ampullae of large size, which have a single wide 

 aperture of about the same diameter as the ampullae themselves, into an 

 exhalent canal. The ampullae are also set radially or vertically to the 

 cavity of the canal. This type is seen in the Sylleibid genus Polejna 

 (Calcarea Heterocoeld}' 2 ' ; in Euplectella ; in Halisarca Dujardini, where the 

 ampullae are often branched, and Bajalus ; in Spongelia, Velinea, Aplysilla, 

 and to a less marked degree in Dendrilla?. The differences depend on 

 the degree of complication observable in the inhalent and exhalent canal- 

 systems which are present universally in this and the following type. The 

 exhalent canals are short wide tubes, Polejna (Leucilla] connexiva ; short 

 tubes somewhat branched, P. (Z..) uter ; long tubes, simple in Bajalus, 

 branched in Halisarca Dujardini, in Aplysilla, Dendrilla, Velinea, and 

 Spongelia. The inhalent canals are more or less branched, wide in 

 Halisarca, with pore membranes and subdermal cavities (post] in Bajalus 

 and the Ceratine genera (? Velinea). Both systems of spaces are remarkably 

 large, and the mesoglaea is reduced to mere anastomosing strands irr 

 Etiplectella. The ampullae communicate with the inhalent canals as a rule 

 by many pores, scattered over their surface, Polejna, Eiiplectella, Spongelia, 

 or aggregated at the end opposed to the exhalent aperture, e. g. Bajalus, 

 Aplysilla. The Plakinidae are transitional to the next type, the ampullae 

 frequently communicating with the exhalent canals by a short tube 

 (Vosmaer). In other respects they offer various degrees of complication, 

 e. g. in Plakina monolopha the ampullae may open outwards by a super- 

 ficial pore, whilst Plakortis simplex has subdermal cavities. (4) The 

 ampullae are small, either pyriform with a funnel-shaped exhalent pore- 

 canal, or spherical with a tubular canal. When the inhalent canals are 



1 The subfamilies named have been established by von Lendenfeld, Proc. Lin. Soc. New South 

 Wales, ix. pp. 1090-1110. 



a The family Sylleibidae, with two genera, Vosmaera and Polejna, is due to the same authority 

 (op. cit. p. I no). Polejna corresponds to PolejaefFs genus Leucilla (Calcarea, Challenger Reports, 

 viii. p. 51). Vosmaera is a peculiar type. The ampullae are disposed in a radial fashion round the 

 oscular tube, but communicate with a branched inhalent and exhalent canal system. The genus 

 corresponds to PolejaefFs Leucetta in part, i.e. to L. imperfecta and L. vera. L. Haeckeliana is 

 included by von Lendenfeld through apparently a mistake, as may be seen on comparing his defini- 

 tion, p. 1 1 10, with PolejaefFs figures, op. cit. PL VIII. 



3 Darwinella and lanthella are stated by Polejaeff to agree with Aplysilla (Keratosa, op. cit. 

 xi. pp. 22, 23). 



