42 



-with a small portion of the lower end of the sponge-body, of the size of a hen's 

 egg attached. As is shown by its large dimensions this root-tuft, which is 

 5 cm. thick and 20 cm. long, formed part of a full-grown specimen. 



I base my description on the intact, full-grown specimen. This evidently 

 belongs to a new species of the genus Semijerella, of which hitherto only a single 

 species, viz., SempereUa schultzei Semper, was known. On the whole this fine 

 sponge has the shape of a cucumber ; that is why I gave to it the specific name 

 cucumis. Semperella schultzei Semper, which occurs in the Philippines and 

 Moluccas, is club-shaped and has several projecting longitudinal ridges. 

 Seriiperella cucumis is spindle-shaped, shows a slight S-shaped curvature, and 

 has a circular transverse section. Its upper end is slightly truncate, of a 

 somewhat loose and tufty appearance, and destitute of a simple oscule or a 

 sieve-plate. Thus the two species, although attaining similar sizes, differ con- 

 siderably in outward appearance. Below, the body is broadly truncate as in 

 Semperella schultzei. The root-tuft, which protrudes from the lower terminal 

 face, is about as thick as the inferior end of the sponge-body and appears as a 

 direct continuation of the latter (pi. VIII, f. 1). 



In both species the incurrent areas are coverd by fine quadratic reticula- 

 tions. In Semperella schultzei the oscular areas appear as loose and irregular 

 networks, situated on the projecting, longitudinal ridges ; in 8. cucumis the excur- 

 rent openings are rounded canal-mouths, partly arranged in irregular transverse 

 rows or low spirals and partly scattered irregidarly (pi. VIII, f. 1). 



As in Semperella schultzei, the Avliole body consists of a complicated network 

 of tubes, the walls of which completely separate the continuous excnrrent from 

 the equally-continuous incurrent cavities. These tubes have a more or less 

 circular transverse section and are 5-10 mm. wide. Their walls are 500-2000 a<- 

 thick, and supported by numerous strands of stout macroscleres. 



The root-tuft is 10 cm. long. The spicules composing it form bundles 

 2-5 mm. thick which arise 5-10 mm. apart from the lower face of the sponge. 

 Further down, the bundles join to form a fairly continuous tuft, and at the 

 lower end, which is imbedded in the silt of the sea-bottom, the basalia-spicules 

 slightly diverge. 



The supporting skeleton, composed of macroscleres, forms a rather loose 

 system of rope- or band-shaped spicule-bundles up to 2 mm. thick. These 

 traverse the tube-walls which divide the incurrent and excnrrent cavities, in a 

 more or less regular manner. In the whole of the axial part of the sponge, up 

 to a distance of 1 cm. from the lateral surface, nearly all the bands of macro- 

 scleres are arranged longitudinally ; only here and there oblique transverse bands, 

 connecting the longitudinal ones, are met with. In the distal part of the sponge 

 the spicule-bands anastomose here and there and mostly extend in a radial 



