58 
THE VOYAGE OF H.M.S. CHALLENGER. 
striated. In many of the zocecia, at some distance from the growing edge, but in which 
the polypide is still quite vigorous, a narrow linear band may be seen on either side within 
the perigastric cavity, and anterior to the polypide. These bands are formed by a 
flexuose tube, csecal at both ends, and having thick walls lined with an hexagonal epithel- 
ium. These organs may be probably either ovarian or testicular, but I have failed to 
perceive anything within them beyond the epithelium. Whatever their nature may 
really be, they are perhaps homologous with the peculiar horse-shoe-shaped organ in 
Carbasect moseleyi. They are certainly not parasitic vermicules, although, curiously 
enough, the latter do sometimes occcur in the interior of a zocecium in this species. 
(7) Ccirbasea cribriformis, Busk (PI. XXXIV. fig. 8). 
Carlasea cribriformis, Bk., Brit. Mus. Cat., vol. i. p. 51, pi. lxviii. fig. 1 ; Haswell, Proc. Linn. 
Soc. K S. Wales, p. 37. 
Retepora cornea, Bk., Voy. of Rattles., vol. i. p. 380. 
Character .— Zoarium composed of circular fenestrated fronds, superimposed one upon 
the other, and growing spirally from a common centre, one from the other. Zooecia oval, 
open in front but with a narrow thickened band all round, within the border ; behind 
they are convex, and faintly wrinkled or striated transversely with faint longitudinal 
cicatriciform marks extending the length of the zooecium. Ocecia globose, completely 
immersed in the superjacent zocecium. A wide, thin- walled, flexible, radical tube, 
springs from an aborted zocecium at the lower angle of each fenestra. 
Habitat . — Station 186, Cape York, 8 fathoms, coral mud. Station 188, lat. 9° 59' S., 
long. 139° 42' E., 28 fathoms, green mud. Station 190, lat. 8° 56' S., long. 136° 5' E., 
45 fathoms, green mud. 
[Off Cumberland Island, Voy. of Rattles.] 
The peculiar fenestrate zoarium of this very curious form is at once sufficient for its 
distinction ; the mere external aspect, except as regards the horny consistence, is exactly 
that of a Retepore. Whether it should be included among the Flustridse or should not 
rather be regarded as a quasi-erect Membraniporidan is extremely doubtful. The zooecia 
have a membraniporidan character. The way in which the superimposed fronds or lobes 
spring in a sort of spiral manner from the centre, sometimes to the number of six or more, 
is very remarkable ; but besides this central or initial attachment, the fronds are also 
loosely interconnected by the wide radical tubes springing from the lower angle of each 
fenestra. A condition which is also more or less membraniporidan. 
Mr. Haswell ( loc . cit.) well describes the very peculiar mode of growth in this species. 
