82 
bulletin of the bureau of fisheries. 
and 23 segments. The penis (fig. 1 1, F, p.) is very long, with indistinct traces of annulation. There is a 
pencil of hairs at the tip, and a few sparsely scattered elsewhere. Terminal appendages are very minute, 
about 1.25 mm. long, composed of 8 rather profusely bristly segments (fig. 11, D). 
This species is known by seven individuals, all very similar. It is much smaller than Pachylasma 
giganteum (Philippi) of the Mediterranean and P. aurantiacum Darwin from New South Wales, the 
only species of the genus hitherto known, and differs from them in so many details that a com- 
parison would be superfluous. The specimens had been removed from the crinoids before reaching 
me, and therefore the exact nature of the base could not be ascertained. From the thin, acute basal 
Fig. ii . — Pachylasma crinoidophilum. A, two segments of cirrus v; B, maxilla; C, 1st cirrus; D, terminal appendage; 
E. mandible; F, 6th cirrus and penis. 
edges of the plates of the wall, and the nearly perfect condition of the soft parts, I presume that the 
base is wholly membranous. The base of the cup is hollowed to fit the stem of the crinoid, upon 
which all were seated in a longitudinal position. 
Catophragmus (Chionelasmus) darwini Pilsbry. 
1907. Catophragmus darwini Pilsbry; Bulletin of the Bureau of Fisheries, vol. xxvi, p. 188. 
The Hawaiian barnacle described as Catophragmus darwini Pilsbry, and known by mutilated indi- 
viduals only, has many points of resemblance to Pachylasma crinoidophilum. The mouth-parts, cirri, and 
penis are very similar, and the terga, scuta, and plates of the wall are alike in many respects. In 
