54 Prof. J. D. Dana on two Oceanic Species of Protozoans. 



VI. — On two Oceanic Species of Protozoans related to the 



Sponges. By James D. Dana*. 



The Spharozoum figured below (fig. 1 a) was collected by the 



writer in the Pacific, near latitude 30° N. and longitude 178° W., 



during a calm, on the 26th of May, 1841. 



Fig. 1 a represents the gelatinous globule of natural size. 

 The ocean's waters were filled with this species and another 

 represented in fig. 2 a. The minute dots covering the globule, 

 one of which is magnified in fig. 1 b, were closely crowded, as 

 shown in fig. 1 a. In this respect the species difi'ers widely 

 Fig. 1. Fig. 2. 



from the figure of a species by T. H. Huxley in the ' Annals and 

 Magazine of Natural History,' viii. 433, pi. 16; and as it 

 hence appears to be distinct, the writer has named it Sphterozoum 

 orientate. About the dots, or ocelliform spots (zooids), the spi- 

 cules (supposed to be siliceous) were very numerous and much 

 branched, as in fig. 1 b. The general mass had an exceedingly 

 faint bluish tinge ; the centre circle of the ocelliform spots was 

 of the same tint, while the ring around was of a veiy faint 

 ochreous shade. The globules represented on the ocelliform 

 spots in fig. 1 b were yellow. 



The other species (fig. 2 a) had the same general colour, and 

 similar ocelliform spots as to form, colour, and numbers, without 

 the spicules. Pigure 2 b represents one of the ocelliform spots ; 

 the dots in the surrounding mass correspond to minute yellow 

 globules or cells. This species is included with the Sphcerozoum 

 under the genus Thalassicolla of Huxley. This name has been 

 since restricted to Huxley's T. nucleata, and the name Collo- 

 sphcBra applied to forms much like fig. 2, by Miiller. The mass 

 was less firm to the touch than that of the preceding. A fuller 

 examination of this and the related species is required to decide 

 whether the one here figured is new or not. 



Both of the species had the power of motion by a movement 

 like expansion and contraction, and also the power of sinking 

 and rising at will in the water. No external opening could be 

 distinguished. 



* From the Ameiicau Journal of Science and Arts, May I860. 



