200 Papers from the Marine Biological Laboratory at Tortugas. 



I have placed this species in the genus Bracebridgia with some hesitation, 

 since, as this genus is understood, it possesses no ascopore (Levinsen, 1909, 

 pp. 283, 289). In subsulcata a minute pore is usually present below the 

 suboral avicularium; a similar pore appears above the basal avicularium 

 when this organ is present. This latter pore was not figured nor mentioned 

 by Smitt. I have not been able to determine positively the nature of this 

 structure and it may be, from the fact that it is often wanting and also 

 because of its presence in connection with the basal avicularium, that it 

 is not an ascopore at all, or that it represents this organ in a vestigial 

 condition. 



The nature of the colony and the zooecia with the marginal and other 

 ribs, the form of the orifice, the presence of a line of special independent 

 avicularia on each edge of a branch, all seem to agree with Bracebridgia. 

 B. pyriformis (Busk) has a flattened area below the orifice where the avicu- 

 larium is located in subsulcata, but the fact that MacGillivray found a 

 single avicularium in this position in one colony of B. pyriformis\\s sufficient 

 to show the relationship. Moreover, in the rare cases in which the oral 

 avicularium is wanting in subsulcata there is a flattened area similar to that 

 of pyriformis. 



Genus Retepora Smitt, 1867. 



Retepora marsupiata Smitt. 



Smitt, 1873, p. 67. — Busk, 1884, p. 116 {Retepora atlantica). — Gabb and Horn, 

 1862, p. 138 (Phidolophora labiata). — Jelly, 1889, p. 212 (Jelly adopts Busk's 

 name atlantica for this species, but Smitt's publication of the name marsupiata 

 clearly has priority). 



Taken on a number of occasions at 10 to 18 fathoms. The largest colony 



measured about an inch in height. The color in life is a delicate pink. 



Smitt records the bathy metrical distribution as 16 to 262 fathoms. 



Genus Rhynchozoon Hincks, 1891. 

 Rhynchozoon tuberculatum n. sp. (Fig. 9.) 



Zooecia small, rather evenly swollen, separated 

 by slightly raised marginal walls; the surface, ex- 

 cept in young individuals, strongly tuberculate. 

 Pores are wanting, except for occasional very 

 minute ones at the margin. Orifice ovate, the 

 broader distal border often somewhat straight; 

 at one side near the proximal border a strong 

 pointed tooth extends often more than half-way 

 across the orifice and curves backward ; on the op- 

 posite side a minute projection sometimes appears, pm. c,.— Rhynchozoon tuhercuia- 

 but is often entirely absent. The peristome is thin o"f'^o'2edumSce^ Some! 

 and raised high above the primary orifice, usually andoviceii. 

 erect at the sides, but flaring slightly backward behind the orifice ; above 

 the large tooth the peristome appears to bear a minute, short-elliptical 

 avicularium, but I am not able to distinguish a mandible in my specimen. 



