262 PERCY SLADEN TRUST EXPEDITION 



18. Donatia lyncurium auctorum. 

 (Plate 48, fig. 1.) 



Tethya lyncurium auctorum. 



(For synonymy and literature of tlie species vide Lendenfeld [1896].) 



There is in the collection a single very small specimen, only about 8 mm. in diameter, 

 which appears to me to be indistinguishable from the European form. It has a strongly 

 tessellated surface and a few small, root-like attachment processes, and the colour in spirit 

 is nearly white. 



The cortex is about 0"86 mm. thick and there appear to be no large intracortical 

 crypts. The radiating bundles of the main skeleton pierce the cortex and spread out into 

 wide brushes, the projecting ends of the component spicules of which render the surface 

 slightly hispid. Beneath the cortex the intervals between the well-defined skeletal 

 bundles are occupied by numerous loose styli or subtylostyli radially arranged. 



The large spherasters (Plate 48, figs. \ a, ih) are scattered irregularly and rather 

 sparsely in the cortex. They are abundant in the outer part of the choanosome mixed 

 with smaller forms, possibly developmental stages. When fully grown they measure 

 about 0'07 mm. in diameter. Their sharp conical rays are about half as long as the 

 diameter of the centrum. 



The cortical chiasters (fig. 1 c) are strongylasters or oxyasters, rarely faintly tylote, 

 with usually more than six very slender rays and no conspicuous centrum ; total diameter 

 about 0'012 mm. Curiously enough these spicules appear to be absent from the surface, 

 where, it will be remembered, the cortical chiasters are usually most abundant. The 

 choanosomal chiasters (fig. 1 d) are rare and closely similar in form and size to those of 

 the cortex. 



Previously known Distribution. European Seas, &c. (For further particulars vide 

 Lendenfeld [1896].) 



Register No., Locality, &g. cxx. 2 c, Sqjomon, 10 — 14 fathoms. 



19. Donatia japonica (SoUas). 



(Plate 48, fig. 2.) 



1 Tethya lyncurium, Deszo [1878]. 

 Tethya japonica Sollas [1888]. 

 Tethya japonica Lindgren [1898]. 

 Tethya lyncurium var. a. Dendy [1905]. 

 Donatia japonica Topsent [1906 b]. 

 Donatia parvistella Baer [1905]. 

 Tethya lyncurium Row [1911]. 



(For other possible synonymy vide Lindgren [1898] and Hentschel [1909].) 



There are in the collection nine specimens which I think must be referred to this 

 species. They are all more or less spherical in form, and the surface exhibits the usual 



