CIRRIPEDS FROM THE JUAN FERNANDEZ ISLANDS 489 
The scutum in the fullgrown individuals (fig. 2 g) differs from typical Z. 
australis in the more convex occludent margin, especially in the lower part, 
and in the absence of an umbonal tooth, which is well developed in typical 
australts. 
The ¢ergum is rather short in all specimens, In the typical specimens it 
is much longer. 
The carzza has a well developed fork in all stages studied, yet not with 
so long prongs as in typical L. australis, a feature also pointed out by 
WELTNER. JENNINGS (1915) found that young specimens of typical Z. austra- 
/is have the prongs of the carinal fork scarcely developed and only an in- 
curving at the umbo of either scutum. If this is constant for typical australis 
or only a small variation is not possible to decide at present. 
As in L. australis, all plates are rather thin or even transparent. WELT- 
NER considers his specimens with incomplete calcified plates abnormal. I am 
able to affirm here that all individuals, larger and smaller, have these thin 
plates. The carina is well separated by a chitinous interspace from the scu- 
tum and tergum. This is also to be found in some specimens of typical Z. 
australis. 
Measurements in millimetres: 
Capitulum Pedunculus 
length width length thickness 
21 13 23 4 
16 IO 22 3 
Internal parts: By comparison with the mouth-parts of typical Z. australis 
it can be established that no important differences exist. Generally the mouth- 
parts are of little specific value in the genus Lefas, which has already been 
pointed out (NILSSON-CANTELL, 1921). JENNINGS who (1915) has discussed 
some characters of importance for distinguishing Lefas species, mentions that 
L. australis has three prominent spines at the upper angle of the maxilla I, 
while ZL. hilt and anatifera have only one or two, BROCH (1924) gives for 
L. anatifera two to three such spines, which is in accordance with my own 
experience. In var. we/tnerz I find three spines, but in a dissected specimen 
of typical ZL. australis I find only two. This character is thus no good for 
distinguishing Lefas species. The two typical filamentary appendages are also 
found here. 
Locality: Masatierra, on Macrocystis drifted from the continent, 28. 4. 1917, 
Nos. 594, 595 and 596. Many specimens associated with L. pectenata. 
Distribution: Known before from Talcahuano, Chile, on Macrocystis. 
Genus Balanus. 
B. psittacus (Molina, 1782), Darwin, 1854. Fig. 3. 
Lepas psittacus Molina, 1782. 
Balanus tintinnabulum var. c Ranzani, 1818. 
Balanus picos Lesson, 1831. 
Balanus psittacus Darwin, 1854; WELTNER, 1897; GRUVEL, 1905; PILSBRY, 1909, 1916. 
