B. Porifera incalcaria. 7 



character of Vosmaer's Cornacuspongiae is given as follows: Si licea with usu- 

 ally soft mesogloea, and a skeleton composed of bundles of monaxouid, never 

 tylostylote spicules cemented by spougiu, or of spongiu fibres without proper 

 spicules. Microsclera, when present, inonaxon, never stellate. Those without 

 proper spicules in the supporting skeleton are united to an 'artificial group', viz. 

 Monoceratina, which group is divided into three families. Fam. 1. Aulenidae. 

 Cornacuspongiae of reticulate structure, with extensive and complicated vestibular 

 cavities, and a hard skeleton, which consists of a pretty dense network of more 

 or less areniferous, coarse fibres, to some of which proper echinating spicules 

 [sic] may be attached. Without microsclera. With very small ciliated cham- 

 bers. Aulena, Hyatella. Fam. 2. Spongidae. Cornacuspongiae without 

 proper spicules, with small spherical or pear-shaped ciliated chambers. 

 Five sub-families. A. Eusponginae. wSpougidae with a dense network of 

 solid, simple, smooth fibres. Chalinopsilla n. (probably Velinea Vosm.), 

 Phyllospongia, Leiosella n., Empongia, Hlpposponr/ia, and Coscinodcrma. B. Aply- 

 sininae. Spougidae with a loose, generally very uniform network of pithed 

 fibres. Thorecta n., Thorectandra n., Aplysinopsis n., Luffaria, and Aplijsina. 

 C. Druiuellinae. wSpongidae with thick fibres which arc covered with lobose 

 excrescences; and with exceedingly long special efferent canals to the ciliated 

 chambers." Druinella n. D. Halminae. Spongidae with a skeleton composed of 

 a network of arenaceous threads or large scattered sand grains in the ground- 

 substance." Oligoceras, Dysideopsis n., and Halme. E. Stelosponginae. Spou- 

 gidae with more or less fascicular fibres, and a loose skeleton-net. Stelospongia, 

 and Hircinia. Fam. 3. Spongelidae. Coruacuspongiae with large sac-shaped 

 ciliated chambers, destitute of special efferent canals ; with a transparent ground- 

 substance, and a reticulate skeleton, composed of solid horny fibres free from 

 proper spicules, which generally contain abundant foreign bodies, or may be 

 replaced by large scattered sand grains. Microsclera, when present, sigmata or 

 rods." Two sub-families. A. Phoriospouginae. Spougelidae with proper 

 spicules. sigmata, or rods in the ground-substance." Phoriospongia, and Sigma- 

 tella n. B. Spongeliuae. Spongelidae without sigmata or rods in the ground- 

 substance. Haastia n., Psammopemma, and Spongelia. - - For the rest of the 

 Horny Sponges* a 'natural order' is etablished, viz. Hexaceratina. Silicea 

 with large elongate, oval or tubular, rarely ramified ciliated chambers ; with a 

 simple canal system. The inhalant canals are not clearly distinguished from the 

 subdermal cavities. Without siliceous spicules. Skeleton, when present, composed 

 of pithed fibres, which are entirely free from foreign bodies; and some- 

 times triaxon horn spicules. Three families. 1. Darwinellidae. Hexa- 

 ceratina with large sac - shaped ciliated chambers , and a skeleton composed 

 of dendritic horny fibres and triaxon horn spicules. Danvinella. 2. Aplysil- 

 lidae. Hexaceratina with larg sac-shaped ciliated chambers, with a skeleton 

 composed of pithed horn fibres, but without horn spicules. Janthella, Aplysilla, 

 and Dendrilla. 3. Halisarcidae. Hexaceratina with large sac-shaped or 

 tubular and ramified ciliated chambers, and without horn spicules or a supporting 

 skeleton. Bajalus, and Halisarca. 



Polejaeff had suggested in the Challenger Keratosa, that the polyedric spongo- 

 blasts formed the pith of the spongine fibre, the cup-shaped ones the rind. This 

 he now considers proved by the discovery of a new sponge, Korotnewia desiderata, 

 where the spongin-fibre consists only of what is pith-substance in other Ceratina, 

 and where all the spongoblasts are polyedric. K. belongs to the Darwinellidae, 

 and, as the polyedric spougoblasts are considered to be less 'specialisirt' than the 

 cup-shaped ones, the author believes that group older than e.g. Spongelidae. 



