220 



NA TURE 



[Jan. 5, I 



While no distinct bathymetrical zones, characterized by 

 peculiar forms, can be defined, yet the following table 

 clearly shows that the abundance of fish life decreases 

 with the depth. There have been found between 



Fathoms. 



100-300 ... 



300-500 ... 



500-700 ... 



700-1500 ... 



1500-2000 ... 



2000-2900 ... 



Species. 

 232 

 142 



76 



56 



24 



23 



While no doubt this decrease in numbers is partly due 

 to the extreme difficulty of investigating the deep-sea 

 fauna, it cannot but be also regarded as pretty certain 

 that, while locally abundant as to individuals, the number 

 of species found is but small. 



The descriptions of the new genera and species, though 

 abounding with interesting details in reference to the 

 many strange forms described, cannot with the space at 

 our disposal be even summarized, — they are such as would 

 have been expected from the known skill and judgment 

 of Dr. Giinther ; but we must find room for some allusion 

 to the Report on the structure of the phosphorescent 

 organs, on the head of Ipnops, by Prof. H. N. Moseley, 

 and on the structure of the phosphorescent organs of 

 fishes, by Dr. R. von Lendenfeld. 



In Ipnops tmirrayi the eyes as well as the optic nerves 

 are completely absent, but a pair of symmetrical luminous 

 organs are to be found on either side of the median line 

 of the upper flattened surface of its head, the upper wall 

 of the skull where it covers them being completely 

 transparent. 



These phosphorescent organs are composed of hexa- 

 gonal columnar masses, arranged with considerable regu- 

 larity in rows, and resting inferiorly on a pigmented 

 connective-tissue layer. Each hexagonal column is 

 composed of a number (from thirty to forty) of transparent 

 rods, disposed side by side at right angles to the outer 

 surface of the organ, and with their bases applied against 

 the concave surface of large hexagonal pigment cells, one 

 of which forms the base of each hexagonal column. The 

 basal pigment cells are also hexagonal in outline, and are 

 cup-like, concavo-convex in form, and of the same breadth 

 as the hexagonal columns. These organs receive a rich 

 blood supply, and there appears little room for doubt but 

 that the nerve supply comes from the fifth nerve. No 

 trace of any other nerve supply has been found. From a 

 comparison of these organs with those of a similar nature 

 in other fish, the author concludes that they are but 

 highly specialized and enormously enlarged representa- 

 tives of the phosphorescent organs on the heads of such 

 allied Scopelids as Scopelus rajinesquii and S. metopo- 

 clampus. 



The Report of Dr. von Lendenfeld is of a more general 

 character, treating as it does of the phosphorescent organs 

 of most of the known phosphorescent fishes, though not 

 alluding to those of Ipnops. These organs are classified 

 into the regular ocellar organs and the irregular glandu- 

 lar organs. Both these classes are again subdivided in 

 reference to their form or position ; and in conclusion we 

 have a comparison of the different phosphorescent organs 



of fishes, and of these as compared with similar organs in 

 other animals. 



Dr. von Lendenfeld sums up his investigations as 

 follows: — (i) The phosphorescent organs of fishes are 

 more or less modified glands which have partly been 

 developed from simple slime-glands in the skin, and 

 partly in connection with the slime-canal system ; (2) the 

 typical clavate cells are modified gland-cells ; (3) the 

 accessory reflectors and sphincters are developed from 

 the skin around and below the gland ; (4) the large sub- 

 orbital organs are innervated by a modified branch of the 

 trigeminus, and the other organs by the ordinary super- 

 ficial nerves. 



A splendid atlas of plates accompanies this volume. 

 Of these, sixty-six represent the new species described by 

 Dr. Giinther, and several of them are folding plates ; two 

 illustrate the anatomy of the phosphorescent organs of 

 Ipnops murrayi ; and the remaining five are drawn by Dr. 

 von Lendenfeld and illustrate in a very beautiful manner 

 his Report on the phosphorescent organs just alluded to. 



SALINE DEPOSITS. 



Die Bildung des Natronsaltpeters aus Mutterlangen- 

 salzen. By Dr. Carl Ochsenius. (Stuttgart : E. Koch, 

 1887.) 



THIS book is a very valuable contribution to the 

 history of saline deposits in general, but it is 

 especially useful on account of the author's detailed de- 

 scription of the salt-beds of Chili and Peru, to the study 

 of which he mainly devotes his attention. He discusses 

 the various theories which have from time to time been 

 advanced to account for the formation of Chili saltpetre 

 (sodium nitrate), and shows that it must be regarded as 

 the product of the action of oxidizing guano on certain 

 mother-liquors containing carbonate of soda. 



The salt-beds on the west coast of South America are 

 found in the rainless district which stretches from Payta 

 (near Amotape), in Peru, as far south as the twenty-sixth 

 parallel. This region forms a narrow strip along the 

 coast-line, and rarely exceeds twenty-five miles in width. 

 It is bounded on the east by a chain of the Andes, and 

 in the southern portion of the district the coast is fringed 

 with low-lying hills, known as the coast Cordilleras. The 

 author considers that, before the upheaval of the Andes, 

 salt began to deposit in certain bays, which had been 

 wholly or partially shut off from the sea by the gradual 

 formation of an intercepting bar. Then, while the pro- 

 cess of evaporation was still incomplete, the district was 

 raised by volcanic action, and the mother-liquors from 

 the salt lakes eventually escaped, running down into the 

 valleys, and, where they encountered no obstacle, reach- 

 ing the sea. The coast Cordilleras acted as a barrier in 

 the southern portion of the district ; while in the northern 

 part the liquors doubtless returned to the sea. The vol- 

 canoes which produced the aforesaid upheaval exhaled 

 immense volumes of carbonic acid gas, and the author 

 considers that a portion of the sodium chloride in the 

 mother-liquors was thus converted into sodium carbonate. 

 (The co-existence of borates goes far to confirm the 

 source of carbonic acid.) The coast in this part of Chih 

 is studded with small islands containing deposits of guano 



