T. Davidson — Wliat is a Brachiopod ? 
199 
accomplished in about two hours, wbicb was half tke time it liad 
taken us to ascend. 
From the inhabitants we learnt tkat tbe mountain is regarded as 
being koly, and tbat at certain seasons tbey make solitary pilgrim- 
ages to its sumrnit. We, bowever, had been tbe first to see tbe 
eruption. 
Eartkquakes, altbough so common on tbe mainland, are said not 
to occur bere ; and the only sbocks that bave been feit are tliose 
whick were produced at tbe time of tbe breaking out of tbe volcano. 
Tliis Statement appeared to find some confirmation in the fact of a 
strong eartkquake kaving occurred in Yokohama and Yeddo at tbe 
time of our making our inquiries, witbout being perceived by us. 
Several otber localities in Japan are reported as being free from 
such annoyances ; but bow far these Statements may be relied on 
needs investigation. Some of these districts are in the neighbour- 
hood of recently active volcanos. If it is admitted that in tbe 
immediate vicinity of certain active volcanos, earthquakes are un- 
known, wbilst in tbe surrounding districts tbey are strongly feit, 
tbe idea would at once suggest itself tbat round these particular 
volcanos, conditions exist wbicb ward off the advance of any seismic 
wave. Thus, for example, a lake of lava beneatb tbe unaffected 
area migbt accept a wave, but, for want of proper contact witb tbe 
the rocks above, would be unable to transmit its effect in their 
direction. Owing to the state of tbe weather, and the short time we 
remained upon the island, conditions were very unfavourable for 
making accurate observathms. 
Next morning we set sail for kome, a distance wbicb in coming 
bad been traversed in only six hours; but in returning, tkrougk tbe 
rougkness of botb wind and water, occupied two days. 
II. — What is a Brachiopod ? 
By Thomas Davidson, F.R.S., F.G.S., Y.P.P.S. 
PART II. 
(PLATES IX. and X.) 
( Coniinued from the April Number, p. 155.) 
Musdes . — As tbe nurnber and position of these Organs differ 
materially in the two great divisions into wbicb tbe Brackiopoda 
bave been separated, and to some extent, also, in tbe different genera 
of wbicb eacb di vision is composed, it may be desirable to treat tbis 
subject under two different keads. 1 
ln the Clistenterata, of wbicb tbe genus Terebratula may be taken 
as an example, five or six pairs of muscles are stated by Hancock, 
Gratiolet, and otbers to be connected witb tbe opening and closing 
of tbe valves, or witb their attachment to, or movements upon the 
peduncle. First of all, tbe adductors or occlusors consist of two 
muscles, wkich, bifurcating near tbe centre of tbe shell cavity, pro- 
1 Unfortunately almost every anatomist who has dritten on the muscles of the 
Brachiopoda has proposed ditferent names for each muscle ; hence much confusion 
has arisen which can but be regretted. 
