ZOOLOGY. 315 



these ridges gives rise to four principal horizontal divisions, marked 

 by the absence or the distinct characters of animal forms. The first 

 division includes the top of these ridges, and extends horizontally to 

 various distances, according to the configuration of the shoal. It is 

 composed of sand, mostly quartzose, containing very little feldspar, 

 with some grains of hornblende very much worn, but no animals. 

 This sand, although very fine, is remarkable for its almost stony hard- 

 ness. It has been a question to what this should be attributed. Some 

 have thought that it may be owing to a cement combining with it, but 

 on being dried it is found to lose its compactness. Lieut. Davis 

 thinks that it is produced by the hammering action of the waves. 

 From the second division, which is directly below this, the dredge 

 brings up nothing but broken shells, exhibiting marks of the powerful 

 action of the sea. This division extends to a vertical depth of from 

 three to five fathoms. The third division, next below the second, con- 

 tains pebbles and a few barnacles. The fourth division, at the bot- 

 tom of the interval between the ridges, abounds in animal forms. 

 Every stone is entirely covered with corals or barnacles. It is worth 

 remarking, that the species here existing are not peculiar to this place, 

 but are found under other conditions nearer the surface of the water. 

 Mr. Desor mentioned several species, which on the shoals are found 

 at a depth of from ten to twenty-five fathoms, but in other places are 

 found in very shallow water. These facts are at variance with the 

 opinion of some, that each marine species has its district at a fixed 

 depth below the surface. It may be true of some, however, which 

 are found in brackish or fresh water. The pressure of the water pre- 

 vents the existence of animals at a very great depth, while the beat- 

 ing of the waves, on the other hand, limits their range upwards. On 

 Nantucket Shoals, this is very powerful, and is supposed by Lieut. 

 Davis to be felt to the depth of perhaps ten fathoms. In sheltered 

 harbours, species which on the shoals are compelled to live at the 

 bottom of the trenches can find protection at the depth of a few feet. 

 The fact, that specimens obtained from the deepest water on the shoals 

 are entirely covered with delicate corals, proves the entire quietness of 

 the water. Proc^ofthe Boston Nat. Hist. Society. 



OX THE EXGE-ENA, FROM GABOON, AFRICA. 



WITHIN a few years past, evidence of the most satisfactory nature 

 has been obtained by naturalists and others, showing that there exists 

 upon the banks of the Gaboon River, Africa, a second and gigantic 

 native species of man-like ape, superior in strength and size to the 

 orang-outang. In 1847, four crania, two males and two females, a 

 large portion of a male skeleton, and the pelvis of a female, were 

 brought to the United States. These were the first remains of this 

 animal which had been noticed by naturalists, and were described by 

 Dr. Jeffries Wyman, in a paper read to the Boston Society of Natural 

 History. Three other crania were afterwards sent to England, and 

 described by Prof. Owen. Quite recently, some additional remains 

 have been brought to this country, by Dr. George A. Perkins, late mis- 

 sionary at Cape Palmas, Western Africa. 



