REPORT ON THE TETRACTINELLIDA. 
CXXV 
Genus 2. Chrotella, Sollas. 
Chrotella, Sollas, Sci. Proc. Roy. Dubl. Soc., vol. v. p. 180, 1886. 
The ectosome is a soft cortex, consisting of fibro-vesicular collenchyma, exca- 
vated by extensive intercortical cavities or sinuous canals ; the inner layer is not 
differentiated from the outer, but contains a large number of fusiform cells arranged 
tangentially. 
The spicules of the cortex are scattered through it in various directions, but rarely 
radiately. 
The choanosome consists of granular collenchyma or sarcenchyme, the chamber- 
system is eurypylous or aphodal. 
The excurrent canals may open to the exterior in simple oscules or by a common 
cloaca. 
The somal megascleres are arranged in radiating fibres, which are crossed by loosely 
scattered oxeas lying more or less transversely. 
Type — Chrotella simplex, Sollas. 
There is a second species, Chrotella macellata, which differs from the type in 
possessing large excurrent cloacas, this may be regarded as a character of generic 
importance, but I am unwilling to establish more genera with single species than are 
absolutely necessary. 
Genus 3. Cinachyra, Sollas. 
Cinachyra, Sollas, Sci. Proc. Roy. Dubl. Soc., vol. v. p. 182, 1886. 
The ectosome is a thick cortex, which consists chiefly of a dense fibrous felt of 
fusiform cells, only passing into a thin layer of collenchyma close to the outer surface. 
Cortical oxeas, chiefly confined to the outer three-quarters of the cortex, traverse it 
radially at right angles to the surface. 
The cortex is sohd throughout, without intercortical cavities. 
The excurrent and incurrent apertures are confined to special flask-shaped recesses, 
formed by an inflection inwards of the cortex ; the mouth of each recess is sphinctrate, 
and the walls are perforated by pores, which communicate with the excurrent or incurrent 
canals as the case may be. 
The somal megascleres are collected into fibres which take a spiral course within the 
Sponge ; no separate megascleres are strewn through the choanosome transversely to 
these fibres. 
The mesoderm of the choanosome consists of a granular collenchyma. The chamber- 
system is eurypylous. 
Type — Cinachrya harbata, Sollas. 
