286 COMPARATIVE ANATOMY. 



Description of Fig. 23. 



^, B, C, D, E, the five ambulacra. A, Ambulacrum with covering- 

 plates (i) and extended pinnule (2). B, Ambulacrum with depressed pinnulte. 

 C, Ambulacrum after removal of the pinnulae and covering-plates. D, After 

 the further removal of the side-plates and accessory side-plates (except three). 

 E, After removal of the lancet plates as well. In the centre is seen the mouth 

 with the spiracles surrounding it; in the posterior inter-radius the anus, i, 

 Covering-plates ; 2, pinnulse ; 3, deltoid plates ; 4, their sloping ambulacra! 

 edges ; 5, side-plates ; 6, lancet plate ; 7, pores ; 8, outer or accessory side 

 pieces ; 9, furrow of unknown significance on each side-plate ; 10, radials 

 (fork-plates); 11, aperture of the ambulacral canal; 12, lower lancet plate; 

 13, hydrospire folds. 



We have been deeply interested in the perusal of these books. 

 The ilkistrations, upwards of 850 in number, are all good, and the 

 explanatory text clear and concise. Our best thanks are due to 

 Messrs. Macraillan for the use of the electros and for permission 

 to make the above extracts. 



Arrow-Poisons. — R. Hitchcock refers to the arrow-poisons of 

 the Ainos in a paper contributed to the report of the U.S. National 

 Museum. According to Dr. B. Schreube, the young side-roots of 

 Aconitum Japonicum are gathered in summer and dried in the 

 shade until autumn. Such roots as contain active poison become 

 softer, a process of fermentation appearing to take place, and after 

 removal of their outer coating are rubbed to a pasty mass between 

 two stones. The material is then ready to be spread upon the 

 arrow-heads, or may be preserved, without the poison losing its 

 activity, for five months. The results of chemical and physiolo- 

 gical investigations of the poison by Dr. Stuart Eldridge, whilst 

 confirming the supposition that aconite is the active ingredient, 

 seem to indicate that other, probably inert, substances are also 

 present in the compound. This observer states that the mass, 

 after being mixed, is buried in the ground^ and on its removal 

 appears as a stiff", dark, reddish brown paste, which, before appli- 

 cation to the arrows, is mixed with a certain proportion of animal 

 fat. — Nature^ xlvi., 475. 



