70 UNITED STATES NATIONAL MUSEUM BULLETIN 251 



Larva very large, about 700/a in length. Pigment flecks of sensory 

 organ arranged anteroposteriorly. Its structure resembles that of 

 Didemnum {Didemnum) moseleyi (Herdman). 



Remarks. — The appearance of the colony surface is unique. Di- 

 demnum {Didemnu7n) afersum Tokioka, 1953, also has many finger- 

 shaped protuberances on the test surface, but the shape and the dis- 

 position of these prominences differ distinctly; moreover the shape 

 of the predominant spicules does not conform with those of the present 

 new species. The spicules of Lej)toclinum tonga Herdman, 1886, Di- 

 denvmim (Leptodinum) fuscum Sluiter, 1909, and Didenfunum {Lepto- 

 cUnum) spongioides Sluiter, 1909, closely resemble those of the present 

 species, but none of the characteristic prominences are found on the 

 colony surface in the older species. As colonies showing quite the 

 same appearance were found rather abundantly at different stations 

 in the Palau Islands and even in Philippine waters fairly distant from 

 the Caroline Islands, it seems more reasonable to treat the present 

 specimens as belonging to a distinct new species rather than to include 

 them in any previously known species. 



The specific name nehozita is derived from the Japanese ne^o=cat 

 and sita {zita in combination) = tongue, in allusion to the prominences 

 on the surface of the test, which resemble a cat's tongue. 



22. Didemnum (Didemnum) sphaericum, new species 



FiGUBKS 22a,6 



HoLOTYPE. — USNM 11431; Palau Islands: fringing reef of small 

 island in western part of Eil Malk lagoon of (Mehareliar) ; 7°10'01" 

 N., 134°21'50" E. (HO chart 6078, 1st ed.), 0-10 feet on limestone 

 shelf, with coral and sand, GVF sta. 252, October 27, 1955. 



Paratypes. — USNM 11809, same data, many specimens. 



Description. — Many small, roughly spherical colonies crowded on 

 the branches of an alga of Corallmaceae collected on the Palau Is- 

 lands. The largest one measured 6 mm. in long diameter; but the 

 thickness is very difficult to measure accurately because the colonies 

 are attached to the thin branches of the alga in a spherical form. 

 Very probably they are less than 1 mm. in thickness. 



Test soft and whitish as a whole, rather sparsely impregnated with 

 calcareous spicules so that pale reddish-brown zooids are seen through 

 test. Zooids distributed nearly evenly throughout test. Spicules 

 small, 15-30ju, in diameter in those measured, 21/a on an average ; rays 

 of moderate length, ending bluntly at the tip ; 6 to 8 rays on the equa- 

 torial plane. Superficial spiculeless layer thin, containing some faded 

 pigment cells. Probably the living animal was colored pinkish. 

 Thoracic lacunae well developed. Branchial aperture 6-lobed, retrac- 

 tile muscle of moderate length, 4 stigmatal rows present. Abdomen 

 very small, 300-380/1, in length, and less than 560yu, even when meas- 



