REPORT ON THE POLYZOA. 
47 
1. Didymia, Busk. 
Diclymia, Bk., Voy. of Rattles., Brit. Mus. Cat.; Macgilliv., Nat. Hist. Viet., Dec. v. p. 34. 
Character. — Zocecia joined side by side, all facing the same way. At a bifurcation 
each zooecium of the primary pair giving off a secondary pair. Frontal area almost entirely 
membranous. Ooecia on a third intermediate zocecium at a bifurcation. 
Although the zocecia in Didymia are in close apposition, I am unable to perceive that 
there are any interzocecial pores between them. The polypide has twelve to fourteen 
tentacles, and its mouth opens at once into a dilated cavity, without any apparent 
pharyngeal or oesophageal passage. There is nothing in the form of a so-called funiculus 
besides the bundle of retractor muscular fibres. 
Didymia simplex , Busk. 
Didymia simplex, Bk., Brit. Mus. Cat,, vol. i. p. 35, pi. xxxix. ; Macgilliv., loc. cit., p. 34, 
pL xlvi. fig. 6. Wyv. Thoms., Nat. Hist. Rev., vol. v. p. 145. 
The only species. 
Habitat. — Station 163a, lat. 36° 59' S., long. 150° 20' E, off Twofold Bay, 150 
fathoms, green mud. 
[Bass Strait, 45 fathoms, Voy. of Battles.; Queenscliff, Portland, Victoria, 
Maplestone ; New Zealand, Hutton.] 
2. Dimetopici, Busk. 
Dimetopia, Bk., Brit. Mus. Cat., vol. i. p. 35 ; Voy. of Rattles., vol. i. p. 384 ; Macgilliv., 
Nat. Hist. Viet., Dec. v. p. 34. 
Character. — Zocecia in pairs, apposed back to back ; infundibuliform, with a large 
orifice; each pair facing in a direction at right angles to that of the next; at a bifurcation 
each of the separate zooecia gives off a secondary pair. 
Dimetopia cornuta, Busk. 
Dimetopia cornuta, Bk., Brit. Mus. Cat., vol. i. p. 35, pi. xxix. figs. 2, 3; Voy. of Rattles.; 
p. 384, pi. i. figs. 7, 8 ; Macgilliv., Nat. Hist. Viet., Dec. v. p. 34, pi. xlvi. fig. 5. Wyv. 
Thoms., loc. cit., p. 146. 
Character. — Zooecia contracted below the middle, orifice oblique, wide above; a strong 
conical process on each side above, and one or two long projecting spines in front ; 
inserted below the margin. 
Habitat. — Station 163a, lat. 36° 59' S., long. 150° 20' E., off Twofold Bay, 150 
fathoms, green mud (only a small fragment). 
[Bass Strait, 45 fathoms, Voy. of Battles ; Queenscliff, Sealer’s Cove, Baron v. Muller; 
Portland, Maplestone.] 
