132 MR. W. L. SCLATER ON A NEW [Feb. 16, 



The genus Stephanotrochxis belongs to the section of the Madre- 

 poraria known as the Madreporaria aporosa, to the family Turbi- 

 nolidse of Mihie-Edwards and Haime, and to the section Discocyathoida 

 of Martin Duncan (3), which is characterized as follows : — " Simple 

 Turbinolidse, discoid in shape, not increasing much in height with 

 growth. Free or not. With or without pali in one crown. Colu- 

 mella variable; epitheca also." Step/tanofrochus moseleyamis agrees 

 in every way with the above definition except in the point about the 

 pali, since in S. moseleyanus there are distinctly two crowns of pali. 



IV. Distribution of the Genus Stephanotrochus. 



All the sjtecies of Stephanotrochus hitherto described are deep-sea 

 forms, the depths from which they come varying from 410 to 1009 

 fathoms ; S. moseleyanus comes from a depth of 570 fathoms. 



The geographical distribution, considering the fewness of the 

 specimens dredged, is extraordinary ; seven specimens have been 

 obtained belonging to five different species, procured from such 

 distantly separated places as Pernanibuco, the Azores, Sydney, 

 N.S.W., and the Faroe Channel. 



As was mentioned above, 8. vioseleyanus vi&i AveAgeA in the warm 

 area of the Faroe Chaimel, where the bottom temperature is very 

 high, 46°-5 F. 



V. Anatomy o/ Stephanotrochus moseleyanus. 



The soft tissues of the polype extend from the edge of the cup 

 some distance down the outside wall of the corallum, gradually 

 thinning out ; the line of the extension of the soft parts is marked in 

 the dry corallum by the change of colour from a glistening white to 

 a greyish blue, the colour of the basal parts uncovered by soft 

 tissues. 



As far as I was able to observe, the enteric cavity does extend 

 round the edge of the theca to the outer side, so that the tops of 

 the smaller septa would probably stand up free in the enteron ; the 

 primary and secondary septa are so extremely exsert that the tissues 

 are abnormally stretched to cover them, and so have by the action 

 of the alcohol been split. 



This would rather seem to confirm Koch's theory (5) that the 

 theca is formed from the fused ))eripheral ends of the septa. 



The oral disk, the tentacles, except at their tips, and the outer soft 

 wall of the coral are all of a dark madder-colour ; this colour is due 

 to a substance called by Prof. Moseley (6) Polypery thrin ; it is distin- 

 guished by j)eculiar properties : it is insoluble in water, glycerine, al- 

 cohol, ether, ammonia, potash, or picric acid, but is soluble in strong 

 hydrochloric acid ; it is also distinguished by a ]>eculiar absorjition 

 spectrum, a broad black line including the line D. Prof. Moseley 

 found it in ^tephanotrochvs diadema, in Flabellum, Fungia, and *S'^e- 

 phanophyllia, and many other Coelenterata. 



Tlie soft wall of the coral is divided up by a series of longi- 

 tudinal furrows, which correspond to theinsertionsof the mesenteries ; 

 the ridges between the furrows are further crossed by a number of 

 transverse ridges, so that the whole wall assumes a' very wrinkled 



