334 SIR SIDNEY F. HAHMER ON 
3. Amastigia ceassimaeginata {Busk). 
Caherea crassimarginata, Busk, 1884, p. 28, pi. 11. figs. 1-1 b. S.E. of Buenos Aires-, 
600 fathoms. 
Rootlets running down the margins of the branches. Vibracula covering 
only a small part of the basal surface, and resembling those of A. rudis. 
Although this species is biserial the characters of its rootlets, vibracula and 
scutum are in agreement with those of other species which I refer to 
Amastigia. Waters (1913, Proc. Zool. Soc. p. 480) has suggested that it 
should be placed in Canda. 
4. Amastigia benemunita (Busk). 
Menipea benemunita, Busk, 1884, p. 19, pi. 4. figs. 4, 4 a (specimens from Stations 
30.3 (probaWy 308), 313, 314, 81.5 only). Straits of Magellan, W. of S. end of 
S. America, Falkland Is., .5-175 tathoms. 
Scrupocellaria benetmmita ^ Jullien, 1888, Miss. Sci. Cap Horn, vi. p. 69, pi. 8. 
figs. 1-3. S. of Cape Horn, 99 metres. 
Caberiella benenmnita, Levinsen, 1909, p. 135, pi. 22. figs. 8 ff, 9>b. 'Challenger' 
Exp., Stat. 313. 
British Museum, ' Challenger' OoUection, 87.12.9.69-73. The type-slide is 
87.12.9.70, Stat. 313, E. end of the Straits of Magellan, 5,5 fathoms. Sir 
John Murray thought that a mistake was made in one of the records, and 
that Stat. 303 (slide 87.12.9.69) should have been Stat. 308, the depth of 
which was 175 fathoms, and the locality near the W. coast of the S. end 
of S. America. 
This species has a close resemblance to ^4. nuda, and it is curious that 
Busk did not refer it to his own genus Amastigia. It can be distinguished 
from A. nuda by its much larger scutumj with a large, upturned, truncate, 
distal lobe, and by its flatter branches, which may be at least 7-serial, in 
which all the zooecia appear to meet the basal wall normally', although the 
width of the median zooecia, basally, is less than that of the marginal zocecia. 
The spines of the marginal zooecia are 3, 1 + scutum. Marginal avicularia 
are minute and commonly wanting. Under A. rudis I have alluded to 
Levinsen's account of the basal heterozocecia, which he found in a 'Challenger' 
specimen from Stat. 313. I have not found heterozocecia of this type in the 
British Museum slide (87.12.9.70) fronr this Station, and the specimen seems- 
to have only a single basal heterozooecium closely resembling those of 
A. nuda. In 87.12.9.72, from Stat. 315, basal vibracula as described by 
Levinsen occur ; and they resemble those figured by me (PI. 17. fig. 27) in- 
A. rudis. The occurrence of two different types of basal heterozocecia in 
different specimens of what I think must certainly be referred to the same 
species is an interesting fact. 
The ' Challenger ' slide from Stat. 149, Kerguelen, referred to this species- 
by Busk, appears to belong to A. nuda. 
