THE CCELOM 47 



Professor HUXLEY ' has made such a direct comparison. 

 ' As in birds, the liver [of crocodiles] lies between the 

 stomach and the pericardium, and has a peculiar peritoneal 

 investment, shut off from the great 'sac of the abdomen ; and, 

 as in the ostrich, the whole circumference of the stomach is 

 united by fibrous tissue with the parietes. A fibrous expan- 

 sion extends from the vertebral column over the anterior face 

 of the stomach, the liver, and the dorsal and front aspect of 

 the pericardium to the sternum and the parietes of the 

 thorax, separating the thoraco-abdominal space into a respi- 

 ratory and a cardio-abdominal cavity, and representing the 

 oblique septum of the bird.' Further on we read : ' A broad 

 thin muscle arises, on each side, from the anterior margin of 

 the pubes ; and its fibres pass forwards, diverging as they go, 

 to be inserted into the ventral face of the posterior part of 

 the pericardium, and into the ventral and lateral parts of the 

 fibrous capsule of the stomach, passing between that organ 

 anVl the adherent posterior face of the liver, and being 

 inserted into the fibrous aponeurosis which covers the anterior 

 surface of the stomach and represents the oblique septum.' 



Professor HUXLEY seems, according to BUTLER, to have 

 included the ' omentum ' with the oblique septa in his com- 

 parison with the fibrous expansion and the accompanying 

 muscle of the crocodile. I have already pointed out that 

 ' the entire fibrous expansion which arises from the vertebral 

 column, and extends over the anterior face of the stomach, 

 liver, &c., in the crocodile represents both the oblique septa 

 and the omentum in the bird.' A justification for this 

 opinion is to be seen in the dissection of an emu and one or 

 two other birds. We have occasionally observed that where 

 the posterior part of the oblique septa is free from the 

 abdominal walls, ending, in fact, in & free edge within the 

 abdominal cavity, this edge is really continuous with the 

 horizontal septum, as show r n in the cut (fig. 25). The 

 oblique septum is thus merely a fold of the horizontal septum ; 

 they form one continuous structure. As to the muscles of 

 the crocodile mentioned in the quotation just made from 

 ^H ' 'On .l/i/i' //.'.' loc. cit. p. 568. 



