REPORT ON THE CIRRIPEDTA. 101 



The genus comprises eight species, two of which, Tetraclita rosea, Krauss, sp., and 



Tetraclita coerulescens, Spengler, sp., are represented in the Challenger collection, For 



the determination of the species I have composed the following table : — 



Tetraclita. 



I. Parietes formed by a single row of large tubes, . . Tetraclita rosea, Krauss, sp, 



IT. Parietes formed by numerous rows of tubes. 



1. Tergum with the spur joined to the basi-scutal angla 



(a) Basis membranous, .... Tetraclita jmrpurascens, "Wood, sp. 



(b) Basis thin, calcareous. 



a Radii broad, .... Tetraclita coslata, Darwin. 



/? Radii narrow or absent. 



(a) Surface of the shell corroded, . . Tetraclita porosa, Gmelin, sp. 



(/?) Surface of the shell with narrow, serrated 



libs, ..... Tetraclita serrata, Darwin. 



2. Tergum with the spur not joined to the basi-scutal angle. 



(a) Basis thick, calcareous, .... Tetraclita radiata (Blainville) Darwin. 



(b) Basis very thin, articular ridge of the scutum very 



prominent, ..... Tetraclita coerulescens, Spengler, sp. 



(c) Basis very thin, articular ridge of the scutum not 



very prominent, .... Tetraclita aitiata, Darwin. 



Tetraclita rosea, Krauss, sp. 



Conia rosea, Krauss, Die sudafrikanischen Mollusken, 1848. 

 Tetraclita rosea, Darwin, Balanidse, 1854, p. 335. 



Two specimens of this species were taken in Sydney Harbour (Port Jackson). The 

 two specimens are of a somewhat different size ; the larger one measures 31 mm. across 

 the base, a size a little greater than Darwin says it has (l"l inch). This species was 

 taken from a depth of six fathoms. It must Lave been very near the surface, for in 

 Australia this species lives attached to littoral rocks and shells. 



Tetraclita coerulescens, Spengler, sp. (PI. XIII. fig. 34). 



L'pas coerulescens, Spengler, Skrifter af Selsk., I. 1790. 

 Tetraclita coerulescens, Darwin, Balanida?, 1854, p. .'Hi'. 



H.M.S. Challenger, when at Zamboanga (the most south-western point of Mindanao, 

 Philippines), took some specimens of this species at a depth of 10 fathoms. As there 

 existed differences between these specimens and the description and figures of Darwin, 

 I first thought of describing them as belonging to a different, though nearly related, 



(ZOOL. CHALL. EXr. PART XXV. — 1883.) Bb 21 



