20 DISCOVERY REPORTS 



' cop.m. ', meaning coprolitic mud. These so-called coprolites were almost jet-black, and 

 of the size of mouse droppings, and they were covered with the same substance m 

 flocculent form, or were free from it, according to the scour of the tide in the locality. 

 It was best developed in comparatively shallow water, in a depth of 50 fathoms, when 

 the large ash bucket, to the use of which I found it convenient to revert, came up full of 

 these coprolites, without any flocculent matter whatever. All along the coast the mud of 

 the locality was moulded in a similar way, though it was not so striking. When the course 

 of the cruise took us across the open ocean to Ascension, and thence northwards, we 

 were able to trace the transition of the more earthy shore coprolites into the mineralised 

 and glauconitic pelagic ones". I think the last sentence means that pellets found in the 

 deeper deposits were formed from material of pelagic origin, and not by pelagic animals. 

 Murray and Renard (1891), in describing the bottom samples of the Challenger 

 Expedition, say: " In examining the samples of Blue Muds, and especially those near the 

 mouths of rivers, many oval-shaped bodies, about 0-5 mm. in length, were observed. 

 These were described by some observers as Foraminifera. Mr Murray, after numerous 

 observations, came to the conclusion that they were mostly the excreta of echinoderms, 

 principally of holothurians. When these pellets are voided by the animal they are 

 covered by a slimy substance ; many of them may indeed be united in a chain. In some 

 deposits this dung is exceedingly abundant, but as a rule it is impossible to recognize 

 these oval bodies in any of the organic oozes, and in the Red Clays only some doubtful 

 specimens have been met with. They appear to fall asunder when the deposit is granular, 

 like a globigerina ooze, or when long exposed without being covered up, as in the case of 

 red clays". 



There are two arguments against the supposition that these are holothurian pellets. 

 In the first place the theory entails the existence in considerable numbers and with a 

 world-wide distribution of a small holothurian, about 2 cm. long. That size is arrived at 

 from the diameters of known holothurian pellets, a Holothuria nigra 20 cm. long having 

 a pellet 4 mm. in diameter, and a Cucumaria hyndmani 5 cm. long having pellets with a 

 diameter of 075 mm. Such a holothurian is at any rate not present in the Clyde, where 

 these pellets are very abundant (Buchanan, 1890; Moore, 193 1). In the second place, 

 all the holothurian pellets which I have seen are either in the form of rods, or else of 

 rods constricted at more or less regular intervals by deep clefts, the rods tending to 

 break into short lengths at these constrictions. Also they are characterized by their 

 extreme fragihty, being much more friable than the ovoid pellets of the mud, which 

 remain firm after a hundred years (Moore, 1931) and may even fossilize. Murray him- 

 self confirms their friability. Further, the pellets into which the holothurian faecal rods 

 may break are not ovoid, as are the pellets found in these deep-water deposits, but rather 

 cylindrical, with slightly rounded ends. This shape seems to be fairly constant for the 

 holothurian pellets, as is the ovoid shape for the pellets from the deposits, and it has 

 been shown (Moore, 193 1 a, 193 1 b) that such differences of shape are, when constant, 

 of definite specific importance. 



Murray and Philippi (1908) describe and figure a sample from off the mouth of the 



