260 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



regarded as an unprogressive form, which retains characters of the 

 ancestral stock of the genus, elsewhere found only in an early stage of 

 development. 



The Italian Oligocene species, TetracUta isscli De Alessandri, 1 be- 

 longs to this group and is closely related to T. rosea. 



TETRACLITA ROSEA (Krauss). 



Plate 58, fig. 4. 



1848. Conia rosea KRAUSS, Die Siidafrikanischen Mollusken, p. 136, pi. 6, 



fig. 28. 

 1854. TetracUta rosca Krauss, DAKYVIN, Monograph, p. 335, pi. 10, figs. 



3a-3d. 



Distribution. South Africa ; Australia. 



A single large specimen of this species in the National Museum is 

 labeled " Orange Harbor," no doubt erroneously. No collector given. 

 This specimen is figured (pi. 58, fig. 4) to show the features of the 

 pores. It is 25 mm. in diameter. There is a series in the collection of 

 the Academy of Natural Sciences of Philadelphia from Richmond, 

 near Melbourne, Victoria, collected by Mrs. Agnes F. Kenyon. 



Genus ELMINIUS Leach. 



1825. Elminius LEACH, Zoological Journal, vol. 2, p. 210. 

 1854. Elminius Leach, DARWIN, Monograph, p. 345. 



Barnacle conic or cylindric; compartments four; parietes not 

 porous ; basis membranous. 



Type. E. kingii Gray. 



Distribution. Austral in both hemispheres; littoral. 



Elminius differs from TetracUta by the absence of pores in the 

 parietal walls. It holds such a relation to TetracUta as CJurona to 

 the typical Balani. TetracUta is a more evolved genus. Leach did 

 not mention a species in his table defining this genus. In fact no 

 species had then been described. I am selecting E. kingii, the 

 first species described, as the genotype. 



ELMINIUS KINGII Gray. 



1831. Elminius kingii GRAY, Zoological Miscellany, p. 13. 

 1831. Elminius leachii KING and BRODEKIP, Zoological Journal, vol. 5, p. 334. 

 1854. Elminius kingii Gray, DAKWIN, Monograph, p. 348, pi. 11, figs. Qa-Qe. 

 1911. Elminius kingii Gray, ORTMANN, Princeton Patagonian expedition, 



p. 637. 

 1914. Elminius kingii Gray, STEBBING, Proc. Zool. Soc., London, p. 376. 



Distribution. Falkland Islands, Tierra del Fuego, Chiloe (Dar- 

 win). Darwin describes it as follows: 



Shell smooth, gray, or dirty white ; radii broad, smooth edged. Scutum with- 

 out an adductor ridge. Tergum with the spur distinct from the basiscutal 

 angle. Scutum and tergmn sometimes calcified together. 



> Palceontographia Italica, vol. 12, 1906, p. 318. 



