NARRATIVE OF THE CRUISE. 



239 



The trawlings, with the exception of the failures mentioned above, were very produc- 

 tive, and a large number of new forms were procured. At a trawling in 1900 fathoms, 

 400 miles west of Inaccessible Island, two specimens of a very remarkable new genus of 

 fishes were captured, described by Dr. Glinther as follows : — 



Ipnops. — "This genus belongs to the Scopeloid family; the shape of the body is 

 elongate, subcylindrical, the caudal portion much exceeding the abdominal in length. The 

 scales are large, but deciduous. Fins normally developed. The head is depressed, with a 

 long, broad, spathulate snout ; the mouth wide, with the lower jaw projecting, and armed 

 with rows of minute teeth. 



" The structure of the eyes is quite unique. Externally they appear as a continuous 

 flat cornea-like organ, longitudinally divided into two halves, which covers the whole of 

 the upper surface of the snout and partly overlie the bone. The functions of the organ 

 are difficult to determine. From Professor Moseley's examination it seems at present 

 probable that it is an organ of modified vision and not of luminosity as I at first believed." 



Mr. John Murray was the first to examine by means of sections the structure of the 

 organs, and point out their remarkable peculiarities. Professor Moseley, who has lately 



Fio. 97. — Ipnops murrcuji, Gunth. 1600 to 1900 fathoms. 



re-examined the eyes of this fish by means of Mr. Murray's preparations, writes : — 

 " Their structure is quite unique. They are flattened out to an extraordinary 

 extent, closely united together along a straight line traversing the middle line of 

 the snOut, and at first sight appear like a single white patch or label covering the 

 whole upper surface of the snout. Each eye is covered by a transparent flat mem- 

 brane probably the representative of the cornea, beneath which, and separated from 

 it by a shallow chamber filled with fluid, is a retina of very remarkable structure. The 

 retina extends over the whole area covered by the cornea, and is composed of a layer of 

 remarkably long rods, without, as far as can be detected, any cones. The rods, which 

 break up with more than usual readiness into transverse disks, have their free ends 

 turned towards the pigmented choroid. A very thin layer of nerve fibres intervenes 

 between them and the light, and apparently represents the entire remaining layers of the 

 retina usually present. The choroid is divided into a series of hexagonal areas which 



