78 OBIGINAL AETICLES. 



the teeth, in the different species of Elephant, and the numbera of 

 the ribs and dorsal vertebrae, we obtain the remarkable result that, 

 as the latter numbers decrease, the laminae become narrower. In 

 E. africanus these laminne are widest, and here we also find the greatest 

 number of dorsal veriebraB and pairs of ribs : E. sun atr amis, in 

 which the laminae are narrower, has twenty dorsal vertebrae and pairs 

 of ribs : E. indicus, in which they are stiU narrower, only nineteen. 

 In the Mammoth, {E. primigenius) where they are narrowest of all, 

 the number of dorsal vertebrae and ribs, appears to be only eighteen.* 

 As tlie conclusion of this short notice, we may remark that 

 Cu\ier, by neglecting to compare together specimens of the different 

 species of Elephants, and to attend to the numbers of their dorsal 

 vertebrae and ribs, deprived himself of the discovery of the third 

 living species of Elephant, and thereby missed a principal argument 

 for his assertion, that E. primigenius belonged to a different species 

 from those now in existence. Had he not lost this piece of evidence 

 he would have obtained an overbearing argument in the last-named 

 question, and Naturalists would have become acquainted with the 

 existence of a third species of Elephant, half a century sooner. 



VIII. — Obseevations ok some Australian akd Eeegeean 



HeTEROCTATHI A3fD THEIR PARASITICAL SiPITNCULUS. By Johu 



Denis Macdonald, E.K, F.E.S., Surgeon of H. M.S. "Icarus." 



In two separate casts of the lead off the Bellona Eeef, Lat. 21. 

 51. S., Long. 159. 28. E., we obtained specimens of living Polypi, 

 referable, as Dr. Gray has since very kindly informed me, to the genus 

 Heterocyathus, and on comparing them with others previously 

 collected by me in the Eeegee group, I found that they were specifi- 

 cally different, though ob\aously belonging to the same genus. 



The corallum is simple, free, depressed, broad and flattened at 

 the base, becoming smaller towards the cali/x or oval disc, which is 

 more or less oval in figure, and comparatively shallow, with a well- 

 developed septal system following the regnant number six. 



The septa are disposed in three sets, or whorls, according to the order 

 of their development, viz. a primary set, which is most prominent and 

 madeup of six or twelve members, a secondary, equal in number and 

 alternating with these, and a tertiary set, of double that number and 

 alternating with the other t^A^o. The primarxj septa have, on either 

 side, a thin sub-parallel lamina, with which they are blended at the 

 thecal margin, being only connected with them internally by means 



• That the Mastodons form, not a diverging, but a parallel series with the 

 Elephants, seems evident from the wiiolly ditierent form of their tusks, also from the 

 fact that the Mastodon gujanteus has only twenty dorsal vertebra; and an equal 

 number of ribs— that is less than E africanus—yjYnhi the knobs of the teeth are 

 far larger than those of the last-named animal. 



