Mr. J. E. Gray on Starfish. 275 
the bone earth (phosphate of lime Ca® F°) is the manure, and 
that this substance only does good in such a soil as is poor in 
it, which is said not to be the case in Mecklenburg and north- 
ern Germany, on which account no such astonishing success 
has been seen to result from manuring with bones. On the 
contrary, the English soil is said to have been exhausted of 
its phosphate of lime by the repeated cultivation of wheat, so 
that in it this manure is very successful. We have shown in 
the commencement the views which the author takes of the 
action of mineral substances as manures, and, according to it, 
the action of several, as lime, marl, gypsum, &c., are explained; 
if these substances are not present, or are in only small quan- 
tities in the soil, then they must be added, and in order to 
ascertain this it is absolutely necessary to examine the soil 
chemically. If one wishes to manure with marl, both the 
marl and the soil must be first examined, for marls are very 
variable in their composition, and it is not every one of them 
which will suit one particular soil. 
From M. Pabst we have received another very important 
work on Agricultural Giconomy*, which treats of the cultiva- 
tion of plants agriculturally, but it is quite practical. He who 
wishes for any information concerning the cultivation of those 
domestic plants which can be produced in our country, will 
find in this work sufficient instruction. 
[To be continued. ] 
XXXII.—A Synopsis of the Genera and Species of the Class 
Hypostoma (Asterias, Linneus).. By Joan Enwarp Gray, 
Esq., F.R.S., Keeper of the Zoological Collection in the 
British Museum. 
[Continued from p. 184.] 
Fam. 3. Pentacrrotipa2, Gray, Syn. Brit. Mus. 
The body supported by roundish or elongated pieces, covered with 
a smooth or granular skin, pierced with minute pores between the 
tubercles. 
A. Pentacerotina. Body pentagonal or suborbicular, rays short, 
dorsal wart single, the ambulacra edged with a series of small spines 
divided into rounded groups. 
a. The ambulacra with a single series of large spines near the edge. 
* Body suborbicular, conver above and below; covered above and 
below with granules, and scattered conical tubercles. 
* Lehrbuch der Landwirthschaft. Zweiten Bandes. 1° Abtheilung Spe- 
cielle Productionslehre. Darmstadt, 1839. 
T 2 
