305 
40 mm) pinnate ones, provided with 12—15 pairs of alternate 
branches. 
In om the Korea-Strait (Capt. E. Suenson). Depth 50 fath. 
Hydrali man ia (Hincks) Lev. 
The aperture is provided with two lateral teeth between wkicli 
aie found a deeper adcauline and a much lower abcauline sinus, 
which is not divided by a median projection. The opercular 
apparatus is formed by a much larger adcauline and a small ab¬ 
cauline membrane, the former of which is provided with a free 
valvular portion (PI. V, figs. 1—7). 
I have already pointed out 1 ) that the characters on which 
Hincks has instituted the genus Hydrallmania are only of specific 
ualue, and, therefore, the question if the genus has a right to stand 
depends on whether the aperture and the opercular apparatus 
piesent sufficiently great differences from those found in the other 
genera. The above diagnosis shows that the aperture may be 
regarded as an inverse Æerføfana-aperture, and, therefore, there 
may be set forth reasons both pro and contra the independence 
uf the above genus, which, for the present I propose to keep. 
Besides the three species, H. falcata L., II. distans Nutt. 2 ) and 
H. fransiscana Trask 2 ), all of which have their bases placed in 
the same longitudinal belt and only differ from each other in minor 
details regarding the form and mutual position of the hydrothecae, 
I must to this genus still refer the species which All man has 
described as Thujaria plumulifera. 
Hydrallmania plumulifera (Allman). 
Thujaria plumulifera Allman, Memoirs Mus. Comp. Zoology Vol. V. No. 
2, Cambridge 1877, p. 27, pi. XVII, figs. 3—6. 
Jåderholm, Bihang till Iv. Svenska Vetensk. Akadem. 
Handl. B. 21, Afd. IV, No. 6, 1896, p. 12, Taf. II, 
__%• 4. 
*) 88. 
2 ) 44. 
Vidensk. Meddel, fra den naturh. Foren. Bd. 64. oa 
