A NEW GENUS AND SPECIES OF BARNACLE 

 FROM ECUADOR 



(Plate 27) 

 By I. E. Cornwall 



Hopkins Marine Station of Stanford University 



TETRABALANUS, new genus 



Diagnosis: Sessile barnacles, the shell having four plates; the plates 

 forming the walls have pores which are crossed by cross-septa. Pores 

 arranged in one row between outer and inner lamina, as in many species 

 of Balamis. No epidermis could be seen on any of the specimens examined. 

 The outer surface of the shell is smooth, and the color is white. The lower 

 part of the inner surface is ribbed, but the ribs do not extend as far as 

 the sheath. The lower margin of the sheath does not hang free, as the 

 space between it and the inner lamina of the shell is filled solidly. The 

 ribs on the interior of the shell correspond with the septa between the 

 pores. 



Shell: The four plates forming the shell are arranged in the 

 same way as those of Tetraclita. The rostrum has radii, and is therefore 

 a composite plate formed by the fusion of the true rostrum and the 

 adjacent rostrolateral plates on each side of it. The carina has alae. The 

 lateral plates have alae on one side and radii on the other. The basis is 

 thick at the edge where it is attached to the compartments, and it is thin 

 at the center; it has pores and is smooth on the interior surface. The basis 

 is flat, not cup shaped as the basis of Creusia, as it is attached to rocks or 

 other support. 



Terga: The general shape of the terga resembles quite closely that 

 of Balanus ampJiitrite, but the crests for the attachment of the^^ depressor 

 muscles are more regular. 



Scuta: The scuta also resemble those of Balanus amphitrite. 



Type: Tetrabalanus poly genus, new species. 



Distribution: Dr. Waldo L. Schmitt collected several specimens of 

 this genus in shore collecting at Puna Island, Ecuador, in 1934. All 

 these specimens are attached to stones. 



[227] 



