Prof. F. J. Bell on Araphiura Cliiajii^ Forbes. 411 



fig. 9), the median tooth being simple and spine-like, and not 

 tricuspid, as in ^. Bottgeri. 



Maltzan compares his shell with A. Owenii of Adams and 

 Reeve ; but that unsatisfactory form I am inclined to locate, 

 as has been done bj von Martens (Ann. & Mag. Nat. Hist. 

 1867, vol. XX. p. 105), with the varieties of A. Mans. 



EXPLANATION OF PLATE XVII. Figs. 1-6. 



Figs, \, 2, 3. Lateral view of three specimens of the shell of Argo7iauta 

 Bottgeri, showing variation in the number and prominence of 

 the tubercles. 



Fig. 4. The lower mandible of the beak. 



Fig. .5. The upper mandible. 



Fig. 6. A single row of teeth of the odontophore. 



LVII. — Note on the Variations o/Amphiura Chiajii, Forbes. 

 By F. Jeffrey Bell, M.A. 



Dr. John Murray, F.R.S.E., while dredging off the Avest 

 coast of Scotland, collected a large number of examples of 

 Amphiura Chiajii^ which he has been so good as to present 

 to the Trustees of the British Museum. An examination of 

 these and a comparison of them with the accounts given by 

 preceding writers reveal a wide range of variation. As the 

 variations of described species are now recognized as being 

 much more important and interesting than the descriptions of 

 new forms, I make no apology for directing attention to this 

 Ophiurid. 



The first point to which attention may be directed is the 

 length of the arms. Mr. Norman, in his well-known paper 

 on British Echinoderms *, gives as one of the characters of 

 the species, " Arms extremely long and very slender," or 

 uses an expression which is verbally similar to that which he 

 applies to the eminently long-armed A. filiformis. Among 

 the specimens collected by Mr. Murray there are none which 

 justify the use of the adverb " extremely 5" on the other hand, 

 Forbes's remark that the length of the arms varies in different 

 specimens is certainly confirmed by the numerous specimens 

 collected off the west coast of Scotland. 



The arms of young forms are perhaps proportionately 



* ' Annals,' [3] xv. p. 107. 



29* 



