152 REPORT—1843. 
lipora serpens in 20 to 40 fathoms. Retepora abundant between 15 and 30. 
Alecto incrusting shells in 150 fathoms. Four species of coral were taken, 
though dead, at 105 fathoms. Hudendrium was found at 20 fathoms. Val- 
keria and Campanularia at 30. Crisia at 20. Aectinia ranged from the 
surface to 20 fathoms.- Aleyonium as deep as 70. 
Amorphozoa. 
Sponges abound in the Agean, inhabiting all depths of water between sea- 
mark, where the rocks are often of a brilliant scarlet with incrusting species, 
to nearly 200 fathoms, a sponge allied to Grantia having been dredged alive 
at 180 fathoms, and a small species of another genus at 185. The sponge of 
commerce is procured by divers from rocks in various depths between 7 and 30 
fathoms. Most of the larger species are found at lesser depths, very large ones 
occurring in the second zone or region. The forms of the species do not appear 
to bear any relation to the depth in which they are found, tubular sponges, 
globular, incrusting and palmate species all inhabiting the littoral zone. I met 
with about twenty species of Amorphozoa in the eastern Mediterranean. 
The distribution of marine animals is determined by three great primary 
influences, and modified by several secondary or local ones. The primary 
influences are climate, sea-composition and depth, corresponding to the three 
great primary influences which determine the distribution of land animals, 
namely climate, mineral structure and elevation. The first of these primary 
marine influences is uniform in the eastern Mediterranean. From Candia to 
Lycia, from Thessaly to Egypt, we find the same species of Mollusca and 
Radiata assembled together under similar circumstances. The uniformity 
of distribution throughout the Mediterranean is very surprising to a British 
naturalist, accustomed as we are to find distinct species of the same genera, 
climatally representative of each other, in the Irish and North seas, and on the 
shores of Devon and Zetland. The absence of certain species in the gean 
which are characteristic of the western Mediterranean, is rather to be attri- 
buted to sea-composition than to climate. The pouring in of the waters of 
the Black Sea must influence the fauna of the Zgean and modify the consti- 
tution of its waters. To such cause we must attribute the remarkable fact, 
that with few exceptions individuals of the same species are dwarfish com- 
pared with their analogues in the western Mediterranean. This is seen most 
remarkably in some of the more abundant species, such as Pecten opercularis, 
Venerupis irus, Venus fasciata, Cardita trapezia, Modiola barbata, and the 
various kinds of Bulla, Rissoa, Fusus, and Pleurotoma, all of which seemed 
as if they were but miniature representatives of their more western brethren. 
To the same cause may probably he attributed the paucity of Meduse 
and of corals and corallines. Sponges only seem to gain by it. The 
influence of depth is very evident in the general character of the 7Egean 
fauna, in which the aborigines of the deeper recesses of the sea play an im- 
portant part numerically, both as to amount of species and individuals. 
The secondary influences which modify the distribution of animals in the 
/Egean are many. First in importance ranks the character of the sea-bottom, 
which, though uniform in the lowest explored region, is very variable in all 
the others. According as rock, sand, mud, weedy or gravelly ground pre- 
vails, so will the numbers of the several genera and species vary. The 
presence of the sponges of commerce often depends on the rising up of peaks 
of rock in the deep water near the coast. As mud forms by much the most 
extensive portion of the bottom of the sea, bivalve Mollusca abound more indi- 
vidually though not specifically than univalves. As the deepest sea-bottom is 
