MELONELLA OVATA. 207 
Family.—ANOMOCLADINA. 
Genus.—MBLoneELLA, Zittel. 
1878. Studien iiber fossile Spongien, II. Abhandl. der k. bayer. Akademie der 
Wiss., Cl. ii, Bd. xiii, Abth. i, p. 184. 
Syn.—Siphonia, Groldfuss, Quenstedt (in part); Emploca, Taxoploca, Sollas ; 
Emploca, Vosmaer. 
Subspherical, hemispherical, or ovate sponges; the lower portion either 
widened or supported on a short stem. Cloacal cavity deep, funnel-shaped, with 
the apertures of the excurrent canals arranged in longitudinal rows. The 
excurrent canals follow the curved contour of the sponge and open into the 
cloacal tube; the incurrent canals extend from the ostia on the surface in an 
obliquely curved direction towards the centre of the sponge. The skeleton 
consists of a close mesh of connected spicules of the Anomocladina type, like those 
of the genus Cylindrophyma, Zittel, in which, from twin nodes connected by a 
short rod-like axis, several arms or rays are given off which expand at the ends 
and connect with adjoining nodes (Part I, p. 71, fig. 5b). The lower portion in 
some specimens is enveloped in a dermal layer. 
The type species of this genus is Melonella (Siphonia) radiata, Quenstedt 
(‘ Der Jura,’ p. 679, pl. Ixxxu, fig. 13); from the Upper Jura of Heuberg. There 
is a close similarity in the canal system of this form to that of the Cretaceous 
genus Siphonia, but the spicular structure is markedly different. 
15. Metonztia ovata, Sollas, sp. Plate XIII, figs. 1, 1a—e. 
1883. Empnoca ovata, Sollas. Quart. Journ. Geol. Soc., vol. xxxix, p. 542, 
pl. xx, figs. 1—6. 
1887. _ — Vosmaer. Porifera, Bronn’s Klassen und Ordn. des 
Thier-Reichs, Bd. ii, p. 257. 
1888. Taxoproca — Sollas. Challenger Report, Zoology, vol. xxv, p. xxviii. 
Sponges ovate to sub-cylindrical, sessile, attached directly by their bases to 
shells or other bodies. Of the two specimens known one is 42 mm. in height by 
30 mm. in diameter, whilst the other is 45 mm. by 22 mm. No dermal layer is 
present. The cloacal aperture is from 5 mm. to 6 mm. in diameter; the ostia of 
the surface are numerous, about *5 mm. in width, and separated from each other 
by about the same interval. The canal structures are only partially shown in the 
specimen, which has been longitudinally sectioned; both the incurrent and 
excurrent canals appear to be nearly of an equal width, about -5 mm. The 
