78 THE VOYAGE OF H.M.S. CHALLENGER. 
Genus 8. Mussa, Oken. 
Mussa, (pars), Oken, Lehrb. der Naturg., i. p. 73. 
Fr Milne-Edwards and Haime, Cor., ii. p. 328. 
3 Duncan, Rev. Madrep., p. 82. 
Five species of this genus were obtained. 
1. Mussa fistulosa, Milne-Edwards and Haime. 
Mussa fistulosa, Milne-Edwards and Haime, Cor., ii. p. 332, pl. D. 3, fig. 3. 
Of this well-marked species a single large specimen was obtained. The septa are 
very variable in different parts of the specimen, sometimes being very thick and almost 
swollen, and, not: infrequently, quite small and thin. A curious hard and_ thick 
styliform columella is formed in one cup, due to the lodgment of foreign matter in the 
ealicle. The depth of the cups is frequently less than 1 em. 
Locality.—Kandavu, Fiji. 
2. Mussa multilobata, Dana. 
Mussa multilobata, Dana, Zoophytes, p. 182, pl. viii. fig. 2. 
A single specimen of this species was obtained. In some parts a very strong 
epitheca is developed, while on others it is quite rudimentary, leaving bare the nearly 
smooth surface with its striate and rarely spinose coste. The specimen described by 
Milne-Edwards and Haime under this name seems to be a different form, more closely 
allied to the Mussa echinata than to this species. 
Locality. —Banda. 
3. Mussa echinata, Milne-Edwards and Haime. 
Mussa echinata, Milne-Edwards and Haime, Cor., ii. p. 337. 
This species is close to the Mussa multilobata, Dana, but is readily distinguished by 
its very spiny wall, which is often much thickened, and by its more numerous and 
rather thinner septa. Often the series are very short, and, not infrequently, many 
ealicles become isolated. A strong epitheca is occasionally present on many parts of 
the colony. The Mussa multilobata, Milne-Edwards and Haime, does not seem to be 
different from this species. 
Locality.—Amboina. 
