the Cirripede Genus Stramentum. 71 
S. pulchellum. A MS. label is on the specimen bearing the 
words ‘“ Loricula pulchella,”’ and I can see no characters in 
the specimen to make one dissent from that determination. 
S. macadami is therefore considered here to be a synonym 
of S. pulchellum. 
Measurements.—The largest species appears to be S. pul- 
chellum. The holotype has a length of 26°6 mm., its breadth 
is 15°2 mm., and the length of the scutum is 86 mm. This 
is surpassed by the two specimens (PI. III. figs. 1, 2) originally 
described as S. darwini, for the original of fig. 1 has a length 
of 35°2 mm. (incomplete), a breadth of 22 mm., and a 
scutum 1]°4 mm. in length, while the original of fig. 2 has 
a length of 44 mm., a breadth of 22°4 mm., and a scutum 
of 13°2 mm. in length and 7°6 mm. in breadth. In the latter 
specimen the carina is 6°38 mm. long and 2°3 mm. wide. 
The original of S. macadami has a length of 24°6 mm. 
and a breadth of 12°3 mm, 
Of the other species the type of S. haworthi is said to 
have a length of 27 mm. and a breadth of 17 mm., and the 
type of S. tabulatum appears to be somewhat smaller ;. 
S. canadensis is from 14-15 mm. long and 7 mm. wide; 
S. pulchellum var. minor is said to attain a length of 20 
mm. and S. pulchellum, var. gigas, a length of 36 mm.; 
S. levissima has a length of 20 mm.; and S. syriacum is 
said to be one-third the length of S. levissima. 
Terminology and Number of Valves in the Capitulum. 
Darwin had only a single specimen of the genus before 
him, namely, the holotype of S. pulchellum, and while this 
was nearly complete so far as the peduncle was concerned, 
it had only three of the capitular valves (see Pl. III. fig. 3). 
That on the right, owing to its shape and to the direction of 
its growth-lines, was considered by him to be the scutum 
and the adjoining plate as the first or upper latus. The 
remaining valve was called the second or carinal latus, but 
between that and the upper latus was a hiatus, believed 
by Darwin to have been filled by a tergum. Besides these 
valves he included in his restoration a carina and a rostrum, 
making ten valves in all, for he assumed that the other 
valves were paired. 
The specimen of S. macadami figured and described by 
Wyville Thomson seven years later was more complete in 
the capitular region, and it included a valve—the tergum— 
not present in the holotype of S. pulchellum, between the 
upper and carinal latera, as well as two opposing linear 
