THE ANNALS 



MAGAZINE OF NATURAL HISTORY. 



[FIFTH SERIES.] 

 No. 82. OCTOBER 1884. 



XXVIII. — The Classijicatory Position of Hemlaster elongatus, 

 Duncan da Sladen : a Rejyly to a Criticism by Prof. Sven 

 Loven. By Prof. P. Martin Duncan, F.R.S., and W. 

 Percy Sladen, F.L.S. 



We have quite lately received from Professor Sven Lov^n 

 his most interesting and valuable work entitled ' On Pour- 

 talesia^ a Genus of Echinoidea.' This beautifully illustrated 

 work was read before the Swedish Academy of Sciences in 

 June 1882, and was published in 1883. 



On studying this most masterly communication, we were 

 impressed that Prof. Lovdn had hardly done himself justice 

 in a criticism upon the zoological position which we have 

 given to a very interesting species of Hemiaster. The criti- 

 cisms are short and sufficiently decided ; but we felt that as 

 they came from the most exact student of the Echinoidea of 

 the age, they demanded our most respectful and candid atten- 

 tion. We both studied the form of Hemiaster to which Prof. 

 Lov^n has given an altogether different generic position ; we 

 both agreed to the description of the species which appeared in 

 our work on the Echinoidea of the Ranikot group of the 

 Tertiaries of Western Sind ; and we are both responsible for 

 the correctness of the drawings on our plate xix. Fortu- 



Ann. & Mag. N. Hist. Ser. 5. Vol. xiv. 18 



