174 



scattered pores. It sinks gradually towards the distal end and rises on either side 

 of the polypide-tube under an obtuse angle into a steeply ascending, narrow 

 portion, which forms the lateral margins of the aperture and fades away at the 

 distal end. 



The polypide-tube fills the entire width of the large, almost semi-circular 

 aperture. It is short, of semicircular transverse section and provided with a 

 collar-shaped outwards curved margin. As the opesiular outgrowths reach but 

 half-way down on each lateral wall, the basal wall of the polypide-tube is formed 

 only by the basal wall of the zooecium. 



Each distal wall which is strongly curved from side to side, and the distal 

 half of each lateral wall have a row of small, uniporous rosette-plates. 



Ooecia are not found. 



Avicularia. On the small fragment only a single, small, trapeziform, falcate 

 avicularium was found, the large, depressed cryptocyst of which is perforated 

 by a small, oval opening. In the proximal end of this we see a small, triangu- 

 lar process, which shows traces of having originated by a concrescence of two 

 lateral halves. On the whole this avicularium bears a close resemblance to that 

 found in »Eschara« Antiopa, d'Orb. (PI. VI c, fig. 4 a). 



A small piece of this species was found on a dry Tridacna, locality not 

 noted. In the structure of the zocEcia this species shows some resemblance to 

 Steganoporella patula Mac Gillivr. S at any rate as they are represented in fig. 20. 

 The avicularia have however another form, and this species is moreover said to 

 be provided with ooecia occupying the place of a zooecium. What the author 

 calls an ocecium might, I think, more correctly be called a deformed zooecium 

 without aperture. 



Labiopora crenulata n. sp. 



(PI. VI, fig. 4 a). 

 The zooecia rectangular or longitudinally hexagonal, surrounded by a rather 

 wide, but not strongly projecting, crenulated and transversely striated cryptocyst 

 margin. The depressed part of the cryptocyst, which is somewhat tuberculaLed 

 and with the exception of the part near the polypide-tube provided with nume- 

 rous, rather large pores, reaches with its opeyular outgrowths the basal wall, 

 which it meets in a continuous, straight, transverse line on the boundary of the 

 distal fourth of the latter. The polypide tube, whose transverse section is roun- 

 ded, has an independent basal wall and is distinctly bilabiate with a more pro- 



1 76, p. 54. 



