226 BRITISH JURASSIC SPONGES. 
This genus is proposed for a group of Jurassic and Cretaceous sponges which 
have hitherto been placed in the genus Stellispongia, d’Orbigny (‘ Prodr. de Pal.,’ 
vol. i, 1849, p. 209). In the type of this genus, S. (Cnemidium) variabilis, 
Minster (‘ Beitr. zur Petref.,’ vol. iv., 1841, p. 30, pl. i, figs. 21—23), from the 
Triassic strata of St. Cassian, the fibres have been shown by Steinmann (‘ Neues 
Jahrbuch,’ 1882, vol. ii. p. 180, pl. ix, fig. 2), and I have myself confirmed his 
observation, to consist of short, simple, blunted, sinuous spicules of an entirely 
different character from the spicules forming the fibres in the Jurassic sponges, 
which, on account of their similarity in growth and in canal structures, have been, 
by Zittel and other authors, placed under Stellispongia. Itis, therefore, necessary 
to place these latter forms in a new genus, and to restrict Stellispongia to forms 
with a spicular structure similar to that of the type species. 
The genus Hnaulospongia, Fromentel (‘ Mém. Soc. Linn. de Normandie,’ vol. xi, 
p- 48), has also been proposed for a sponge which will come under Holcospongia, 
but v. Zittel has pointed out that the characters assigned to it have been based on 
the erroneous observation that the sponge is without canals, and it is therefore 
undesirable to adopt it. 
34, Honcosponcia rioricers, Phillips, sp. Plate XVI, figs. 6—6 c; Plate XVII, 
fig. 2. 
1829. Sponara FLoricEps, Phillips. Geol. of Yorks, p. 126, pl. iii, fig. 8. 
1854. — -- Morris. Cat. Brit. Foss., p. 30. 
1860, — — Wright. Quart. Journ. Geol. Soe., vol. xvi, p. 28. 
1875. a — Phillips. Geol. of Yorks, 8rd edit., p. 235, pl. iii, 
fig. 8. 
1878. — — Hudleston. Proce. Geol. Assoe., vol. v, pp. 417, 494. 
1878. PrroneLua Fioricees, Zittel. Studien, Abth. 3, p. 122. 
1883. STELLISPONGIA SEMICINCTA et CORALLINA (in part), Hinde. Cat. Foss. 
Sponges, p. 187. 
Sponges growing in colonies usually from a blunted conical base. Small 
colonies consist of from three to five individuals, and they are from 20 mm. to 
30 mm. in height and thickness, whilst the individuals in large colonies are 
numerous, and form masses of considerable size, a specimen now in the York 
Museum measuring 150 mm. in length, 90 mm. in breadth, and 70 mm. in 
height. The individuals are obtusely conical or subcylindrical, ranging from 
10 mm. to 23 mm, in length, and from 8 mm. to 13 mm. in diameter. The 
summits are conical, rounded, or truncate, without a depressed area; from the 
centre well-marked, straight, simple, open furrows, from 1 mm. to 1°5 mm. in 
