I 2 



The rope-like columella of this species is very characteristic, and is well exhibited in 

 all three specimens. No stereoplasma is present in any of them, a fact which is sufficiënt to 

 separate the species from the closely allied Platrocyat/uis èrunneus of Moseley. 



IV. Subgenus Phloeocyathus nom. nov. 



Pleurocyathus Moseley [nee Keferstein), Challenger Deep Sea Madreporaria p. 159 



(nom. praeocc). 



The tips of the septa are embedded in stereoplasma : otherwise as Conotrochus. 



10. Ceratotrochus (Phlceocyathus) hospes, n. sp. Plate II. fig. 8, Sa. 

 Stat. 150. o°6'N., I29°7'.2E. 1089 m. 1 Ex. (broken). 



Corallum conical, covered with a thin, dark-brown, speckled epitheca, beneath which 

 numerous fine wrinkles and fine discrete granulation, as well as several bold growth-rings, are 

 visible. No distinct costse exist. 



The calicular margin is circular and the epitheca is folded over it, so that the septa 

 are sunk below it. 



The calicular fossa is deep and, like the septa, is of a dark brown colour, the edges 

 of the septa and the tips of the strands of the columella being nearly black. The septa do 

 not project far into the fossa, and appear even less salient than they are owing to the presence 

 of abundant stereoplasma. They are in six systems and four cycles, the last cycle being absent 

 in a few of the half-systems. Those of the first cycle are slightly the largest. 



Most of the septa touch the columella, which though very deep-seated is fairly promi- 

 nent, and consists of about a dozen low cincinni. 



The corallum of the unique specimen is broken, so that its height cannot be determined, 

 hut the maximum diameter of its nearly circular calicular orifice is close upon 9 millim. 



A worm appears to have inhabited the corallum as a commensal, tunnelling in the 

 stereoplasm. 



From P. èrunneus Moseley this species differs (1) in the absence of costse, (2) in 

 haring the septa sunk below the margin of the calicle, and (3) in the larger columella. 



V. Lochmaeotrochus, n. gen. 



This genus agrees in all respects with Phlceocyathus (—- Pleurocyathus Moseley nee 

 Keferstein", which Martin Duncan regards as identical with Ceratotrochus E. & H.) but differs 

 in forming a bush-like colony bybudding — sometimes dichotomously — near the calicular margin. 



Corallum cylindro-conical, covered with a thickish epitheca which rises higher than the 

 septa, budding near the calicular margin to form a small bushy colony. 



