CIRRIPEDS FROM THE JUAN FERNANDEZ ISLANDS 489 



The scutum in the fullgrown individuals (fig. 2 g) differs from typical L. 

 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 

 australis. 



The tergum is rather short in all specimens. In the typical specimens it 

 is much longer. 



The carina has a well developed fork in all stages studied, yet not with 

 so long prongs as in typical Z. australis, a feature also pointed out by 

 Weltner. Jennings (1915) found that young specimens of typical L. austra- 

 lis 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 L. 

 australis. 



Measurements in millimetres: 



Capitulum Pedunculus 



length width length thickness 



21 13 23 4 



16 10 22 3 



Internal parts: By comparison with the mouth-parts of typical L. australis 

 it can be established that no important differences exist. Generally the mouth- 

 parts are of little specific value in the genus Lepas, which has already been 

 pointed out (Nilsson-Cantell, 1921). Jennings who (1915) has discussed 

 some characters of importance for distinguishing Lepas species, mentions that 

 L. australis has three prominent spines at the upper angle of the maxilla I, 

 while L. hillii 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. weltneri I find three spines, but in a dissected specimen 

 of typical L. australis I find only two. This character is thus no good for 

 distinguishing Lepas 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. pectinata. 



Distribution: Known before from Talcahuano, Chile, on Macrocystis. 



Genus Balanus. 



B. psittacus (Molina, 1782), Darwin, 1854. Fig. 3. 



Lepas psittactcs Molina, 1782. 



Balanus tintinnabulum var. c Ranzani, 181 8. 



Balanus picos Lesson, 183 1. 



Balanus psittacus Darwin, 1854; Weltner, 1897; Gruvel, 1905; Pilsbry, 1909, 1916. 



