THE SESSILE BARNACLES. 259 



TETRACLITA RADIATA (Blainville). 

 Plate 61, figs. 3-3c, 4. 



1854. Tetraclita radiata Blainville, DAKWIN, Monograph, p. 343, pi. 11, 

 figs. 5a-5d. 



Distribution. West Indies ( ? also New South Wales and Suma- 

 tra). 



This was described by Danvin as follows : 



Shell white, with numerous approximate longitudinal ribs ; radii broad, with 

 their summits slightly oblique, internally porose ; tergum with the articular ridge 

 extraordinarily prominent, with the spur not joined to the basisculal angle. 



The white color, the narrowly and closely ribbed parietes, and the broad radii 

 give this species an aspect by which it can be easily recognized. 



The large size of the tergum in comparison with the scutum is a 

 further characteristic mark of this species. Unlike most Tetraclitas, 

 it has often been found on ships. 



Specimens in the United States National Museum were found grow- 

 ing on Balanus tintinnabulum antillensis, Cat. No. 2031, taken from 

 the bottom of a Cape Cod whaler from the West Indies. There are 

 others in the collection of the Academy of Natural Sciences of Phila- 

 delphia from St. Thomas. 



TETRACLITA COSTATA Darwin. 

 1854. Tetraclita costata DARWIN, Monograph, p. 339, pi. 11, figs. 2a-2c. 



Type. British Museum, from the Philippine Archipelago. 



Specimens are in the collection from " East Indies," Isaac Lea col- 

 lection, and Tataan Island, Tawi Tawi group of the Sulu Archipelago, 

 Albatross. 



TETRACLITA CCERULESCENS (Spengler). 



1790. Lepas coerulescens SPENGLEE, Skrivter af Naturhistorie Selskabet, vol. 



1, p. 191. 

 1854. Tetraclita ccerulescens Spengler, DARWIN, Monograph, p. 3 1'J, pi. 11, 



tigs. 



Tataan Island, Tawi Tawi group of the Sulu Archipelago, Alba- 

 tross. Zamboanga, Mindanao, E. A. Mearns. 



TETRACLITA VITIATA Darwin. 



1854. Tetraclita vitiata DARWIN, Monograph, p. 340, pi. 11, figs. 3-3e. 

 Tataan Island, Tawi Tawi group, Sulu Archipelago, Albatross. 



TESSEROPORA, new submenus. 



Tetraclita with a single row of parietal pores. 



Type. T. rosea Krauss. 



Darwin has noted that the pores in the walls of Tetraclita^ become 

 more numerous with age, and at a very young stage there is but one 

 row. The recent species for which this subgenus is proposed, is to be 



