237 
surface is in and around the Gulf of Mexico; that exposed 
‘to the most violent and repeated shocks, the Javanese Archi- 
pelago, of which the island of Sumbava forms nearly the cen- 
tre; while, probably, the most interesting earthquake tract 
now known is the great submarine one in the Atlantic Ocean, 
in latitude 0° to 13° south, and west longitude, from 20° to 23° 
or 24°, 
The places on the earth’s surface as to which earthquake 
information is most wanted, and to be commended to the atten- 
tion of travellers are, the great Ethiopian chain of mountains, 
and interior of Africa generally, Madagascar, Central and 
Northern Asia, where the earthquake regions seem to follow 
the courses of the great northern rivers, north of Lake Baikal, 
the north-west of North America, the Gallipagos Islands, and 
in Europe, Spain. 
The President made some remarks upon Mr. Mallet’s 
Paper. 
Dr. Allman read a paper on the Homology of Organs and 
the Affinities of the Polyzoa and Tunicata. 
In this communication it was the author’s object to demon- 
strate that the affinities between the Tunicata and Polyzoa 
were even closer than what was generally imagined, and that 
almost every portion of the organization ofthe one had its cor- 
responding homologue in the other. The hippocrepean Poly- 
zoa are those which indicate most clearly the unity of type on 
which the two groups are constructed, and a comparison was 
therefore instituted between a Clavelina anda Plumatella. It 
was shown :— 
1. That the respiratory sac of the one was in every parti- 
cular homologous with the tentacular crown of'the other; that 
the arms of the lophophore in Plumatella were represented by 
the “*branchial sinus” in Clavelina, the tentacula in Plumatella 
by the transverse bars or vessels which spring off from cach 
——S se OS 
