I03 



Many specimens were broken off above the base. In perfect 

 specimens the attached part was usually broadened by an epithe- 

 cal deposit, varying up to 3 mm. in thickness. Some specimens 

 were much eroded or dissolved away on the outside, and in 

 these it was noticeable that the epitheca was attached before 

 the septa, the costal edges of which were frequently brought 

 into prominence by the epitheca — and sometimes theca — in be- 

 tween them being removed. Other dead specimens showed 

 intermediate characters to one, in which nearly all the corallum 

 had been dissolved, leaving a cast of the intersepted and other 

 spaces in calcite. 



It will be quite clear from a glance at the table and figures 

 that the number of growth lines is not a character of any im- 

 portance, nor probably due to seasonal changes. The lines con- 

 sist of circular elevations around the corallites, and appear to 

 represent pauses in their growths, which would seem to have 

 restarted with slight constrictions of the calicles. 



It is possible that the specimens 35 to 38 do not belong to 

 this species They cannot be accurately compared with sec- 

 tions of the larger coralla at the same size, since the spaces in 

 the latter are filled in by secondary deposits. They approach 

 the smallest specimens of the other dredgings, but are evidently 

 much younger. 



7. TROCHOCYATHUS CINCTICULATUS (Alcock), 



(PI. II., fig. 2). 



T. cincticiilatus, Alcock, Investigator Deep-sea Madreforaria, 

 p. 17, pi. II., figs 5, 5a (1898). 



I refer four specimens to this species, which is presumably 

 founded on a single corallum, and that an extreme one, perhaps 

 produced by unfavourable circumstances. The epitheca is a 

 difficult character, though probably not a very important one. 

 It is in my specimens a deposit formed as the coral grows by 

 the retreating edge-zone of the polyp, i.e., that part which lies 

 external to the calicle. It covers over the costae, but shows 

 their position as ridges, and fills in the intercostal valleys. It 

 is somewhat obscured by boring organisms and the action of 

 erosion, which seems to have attacked the epitheca first. Al- 

 CGck's specimen in this respect doubtless shows the more typical 

 gro\Ath of the corallum. 



Three cf my specimens closely resemble one another, and 

 show what I consider to be the typical central form of the 

 species, the description of which would be as follows : — 



Corallum broadly or narrowly attached, subcylindrical or 

 conical, straight or curved. Epitheca covering the whole 

 externally to within i mm. of the top of the theca, filling in 

 the intercostal valleys, but showing ridges over the costae. 



