14 

 VI. Cyathoceras Moseley. 



Cyathoceras Moseley. Challenger Deep-Sea Madiepoiaiia, p. 156. 



12. Cxathoccras Tydciiiani n. sp. Plate I. Fig. 7, 7^. 



Stat. 95. 5°43'.5 N., ii9°4o'E. 522 m. 2 Ex. 

 Stat. 105. 6° 8' N., 121° 19' E. 275 m. 5 Ex. 



Corallum elongate-goblet-shaped, attached by a short, curved, cylindrical pedicle. Thecal 

 wall thin, granular. The costse are granular ridges only reaching halfway down the thecal wall ; 

 those of the first two cycles are the most distinct, and even they are not very prominent. 



Calicular orifice nearly horizontal ; calicular fossa very deep. 



The septa, which are only very slightly exsert, have a distantly-granular surface and 

 a sinuous edge. They are 60 in number and their arrangement is decidedly irregular, appearing 

 to be in six systems of four cycles with two extra half-systems intercalated. Those of the first 

 two cycles are much the largest and the most exsert, while those of the other cycles diminish 

 in .size in serial succession. 



Columella ver)- deep-seated and very sharply delimited from the septa, consisting of two 

 or more curling ribbons. 



The appearance of this coral is exactly that of a CarvopJiyllia devoid of pali, or of a 

 Dcsinopliylhiin with a Caryophylliaceous columella. 



Height of corallum 17.5 millim. 



Major diameter of calicle 8 „ 



Minor „ „ „ 7 



CyatJwccras Tydcmani is closely related to C. coi-iui Moseley, which was dredged by 

 the Challenger off the mouth of the Rio de la Plata, and oft' the South-East corner of Australia. 



VII. Trochocyathus Edw. & H., Duncan. 

 There are two species of this genus in the collection. 



Synopsis of t/ic Siboga Deep Sea species of Trochocyathus. 



I. Septa in more than four cycles : pali lamellar : 



1. Septa and pali extremely regular: columella a reticulum of coarse 



granules \. T. caryophylloidcs. 



2. Columella sublaminar: the septa of the fourth cycle usually unite 



with those of the third 2. T. pileiis 



13. Trochocyathus caryophylloidcs n. sp. Plate II. Fig. 10, lo^'. 



Stat. 251. 5°28'.4S., 132° o'.2 E. 204 m. i Ex. 

 Stat. 253. 5°48'.2S., 132° 13' E. 304 m. i Ex. 

 I Stat. 96. S. E. of Pearl Bank, Sulu Archipelago. 15 m. 4 Ex.] 



