318 A. EARL AND ON CYMBALOPORA BULLOIDES 



specimens of the allied genus Discorhina [D. rosacea, d'Orb.). In 

 the Acervuline variety the shell also starts spirally, but the 

 Discorbine portion is extremely small and almost buried beneath 

 an accumulation of scale-like chambers, which are more or less 

 irregularly arranged. D'Orbigny figures a regularly Discorbine 

 specimen, as also does Moebius. Brady mentions the occurrence 

 of specimens of two different sizes in the same gathering, without 

 intermediate specimens between the two, and his figures show^ 

 that the small specimens were Discorbine, and the large ones 

 Acervuline. This accords fairly well with my own observations. 

 The small variety appears to be invariably Discorbine ; at any 

 rate I have never met with a small Acei-vuline specimen. The 

 large variety is almost invariably Acervuline, but there are 

 exceptions. I have met with at least two specimens of the large 

 variety in which the early chambers are entirely and regularly 

 Discorbine and so largely developed that the balloon is entirely 

 hidden when the spiral portion is uppermost. Perhaps the two 

 forms are Megalospheric and Microspheric. 



Mr. Matthews' specimens from Corny Point are all of the small 

 or Discorbine variety, and have the reddish-brown colour which 

 appears to be characteristic of the small form, as it frequently is of 

 its ally Discorhina. They agree generally with the characteristics 

 of the species ; but, so far as I have been able to see at present, 

 none of the specimens have a tube opening into the inner " float "" 

 chamber. The " balloons " are more or less filled with dark, dried 

 sarcode, rendering observation somewhat ditiScult, so that it is 

 possible that there may be a simple basal orifice instead of a tube 

 opening. This seems the more probable from the fact that 

 balsam penetrated pretty readily. The tube is not, however, 

 invariably present, for I have often failed to detect it. When 

 present it differs very much in size and diameter, so that it is 

 very probable that a simple basal perforation may frequently 

 take its place. 



I have left to the last the discussion of the circumstances 

 under which this remarkable gathering of Mr. Matthews was 

 made, because it presents several points of great difiiculty. 

 C yrtibalopora hulloides has hitherto been regarded as a purely 

 tropical form, and one of by no means frequent occurrence. As 

 a rule isolated specimens only are to be found in individual 

 gatherings, and even in the Challenger dredging, Station 185, off 



