132 THE VOYAGE OF H.M.S. CHALLENGER. 



forms brought back by the Expedition. It was obtained at six different Stations, and 

 appears to abound over a wide geographical area, occurring at depths varying from 103.3 

 to 2900 fathoms, — the greatest depth whence any living Brachiopod has been brought 

 up. None of the specimens procured exceeded 7 lines in length by 9 in breadth ; its 

 shell is extremely thin and brittle, almost transparent, smooth and glassy. It bears 

 much resemblance in shape to more than one Tertiary, Cretaceous, and Jurassic species. 



" Discina atlantica, King, is another of the widely spread abyssal forms, and 

 was brought up by the Challenger at six or seven different Stations. Its shell is 

 small, very thin, and semi-transparent. The cirri • proceeding from the edges of the 

 mantle are of great comparative length, equalling the diameter of the shell. 



" Only a small number of the species brought home by the Challenger Expedition are 

 positively known to occur in the upper Tertiaries. Those that are both recent and fossil 

 are Terebratulina caput-serpentis, Terebratula vitrea, var. minor, Terebratella dorsata, 

 Megerlia truncata, Platydia anomioides, and Argiope decollata. None of the abyssal 

 forms have yet been found in the fossil condition ; but if we take into consideration 

 the 120 known species of recent Brachiopoda, 26 of these occur both recent and 

 fossil. The chief object of the Challenger Expedition being to dredge in open seas 

 in various longitudes and latitudes, much time could not be devoted to searching coral 

 reefs and shallow rocky bottoms, where the larger number of species are to be found, 

 and where they often congregate in great number and variety. Thus, for example, about 

 30 species have been obtained from Japanese and Korean Seas ; a large number also 

 are to be found in New Zealand waters, near the Cape of Good Hope, &c. In deep 

 seas with muddy bottoms it is rare to find more than one, two, or three species living at 

 the same spot, and this was amply confirmed by the Challenger Expedition." 



An unfortunate accident occurred on board on the morning of the 25th. Owing to 

 the rugged nature of the ground over which the dredge was dragging, the strain on 

 the dredge rope increased on one occasion so suddenly, that before it could be relieved 

 the hook of one of the spans, to which the leading blocks were secured, broke, and 

 the block striking W. Stokes, a boy, fractured his leg, and otherwise injured him so 

 severely that he died in the afternoon. 



On the 26th March when barely 100 miles from land, the depth was found to be 

 3875 fathoms. Such a rapid increase in the depth not having been expected, only 

 3 cwt. of sinkers had been attached. After 3000 fathoms had run out, there was some 

 uncertainty as to the time that should be occupied by the weights in descending, 

 as hitherto the deepest cast had not much exceeded that depth. Twice, the intervals 

 appearing longer than they should be, the line was checked ; but the strain on it, 

 as indicated by the stretching of the accumulators, showed in a most satisfactory manner 

 that the bottom had not been reached. Finally, when the sinkers did strike the ground, 



