THE SPONGES OF THE WEST-CENTRAL PACIFIC 245 



some is distinctly radiate, with long spicules perpendicular to the surface 

 extending in vague tracts outward from a central point. 



The skeleton shows first these very long oxeas, often 21 [x in diameter 

 and 3 to 5 mm in length. A second type of megasclere is also very abundant. 

 It is usually a tetraxon of the calthrops type (all four rays approximately 

 equal). Nevertheless, some of these spicules are only triaxon. In the latter 

 case, the rays are not all in one plane, as in the case of calcisponge triacts, 

 but are arranged as though they were three rays of a typical calthrops (the 

 fourth ray being missing). The rays of these spicules are often 9 /a by 135 ju 

 in size. Among them are numerous deformed spicules, perhaps to be regarded 

 as modified calthrops. Their rays are commonly bent several times at sharp 

 angles, and are irregularly swollen here and there. The microscleres are 

 abundant sigmaspires, 12 n in chord length, and in appearance are quite 

 typical of the family Craniellidae. 



This species is sharply set off from all others in the genus by its lack of 

 either anatriaenes or protriaenes, both of which are typically present. Perhaps 

 a few such might be discovered if a large fraction of the specimens were 

 boiled out in nitric acid, but in this case it would still be appropriate to 

 characterize the present species as notably deficient in triaenes. The species 

 name selected refers to this lack. 



There is one other species of Paratetilla which is clearly very closely 

 related to lipotriaena. This is P. eccentrica, Row, 1911, page 306, from the 

 Red Sea. It also has the curiously deformed spicules abundantly present but 

 is well provided with triaenes. 



ORDER CARNOSA Carter (or CARNIDA*) 



FAMILY HALINIDAE de Laubenfels 



GENUS SAMUS Gray 



Samus anonyma Gray 



Text Figure No. 169 



This species is here represented by a spicule in a microscopic preparation 

 which is, at present, in my collection. This spicule was taken from my Speci- 

 men No. M. 499, Cliona schmidtii. 



This was collected on September 2, 1949, by divers in Komebail Lagoon, 

 northwest of Koror, in the Palaus. The depth was 5 meters, and the substrate 

 was dead coral. 



Gray, 1867, page 526, described Samus anonyma from the West Indies, 

 as a sponge occurring in the burrows of Cliona, but separate from the Cliona. 

 It is sharply characterized by peculiar spicules which are amphitriaenes ; that 

 is to say, there is a short central rhabd and three clads at each end. These clads 

 often have the "dicho" modification. In the case of this Samus from the 



See footnote on page 4. 



