66 Reviews and Notices of BooTcs. 



suddenly upon a bank of them slowly drifting -with the tide. Under 

 these circumstances, however, they are not altogether at the mercy of 

 the current ; and it is curious to see how they resist its action by 

 stretching their tentacles in a straight line in opposite directions and at 

 right angles with the vertical axis of the body. I have also satisfied 

 myself that they are aware of the approach of danger ; for day after 

 day I have seen thousands of them, which were quietly moving near 

 the surface with the mouth wide open in search of food, suddenly turn 

 upon themselves and with a quick jerk dive into the deep as my boat 

 drew nearer and nearer. In fact, all Acalephs dive away from the sur- 

 face when approached, and make accelerated motions to escape the net 

 or glass dipped into the water to catch them. It seems as if they were 

 endowed with the power of seeing, for noise has no effect upon them." 



In the earlier chapters of the work much space is devoted to 

 the classification of the Acalephs in general, and their place 

 among the Radiates. This as held by the author may be repre- 

 sented by the following table, the groups being numbered from 

 the lowest to the highest. 



Province Radiata. 



Class I. Class II. Class III. 



Polyps. Acalephs. Echinoderms. 



Order 1. Actinoids. Order 1. Hydroids. Order 1. Crinoids. 

 2. Alcyonoids. 2. DiscopTiores. 2. Asteroids, 



3. Ctenophores, 3. Echinoids, 



The only fairly disputable point in this table is the question 

 whether the Acalephs are not lower than the Polyps, a question 

 on both sides of which much may be urged, but on which we 

 are scarcely as yet inclined to agree with Prof, Agassiz. 



One important point to geologists illustrated in this work is 

 the affinity of the Millepore corals with the Acalephs rather than 

 the Polyps, and the consequent probability that the orders Tdb- 

 ulata and Rugosa, which are the prevailing Palaeozoic corals, 

 and which have built up so many of our Silurian limestones, are 

 also Acalephs. j. w. d. 



The Romance of Natural History.^ By Philip Henry Gosse, 

 F.R.S. 3*72 pp. demy 8vo ; twelve plates. London : Nis- 

 bet & Co. Montreal : B. Dawson & Son. 



{From the Zoologist.) 



" There are more ways than one of studying Natural History. 



