OCR Text |
Show 1890.] HELODERMA SUSPECTUM. 199 ryngeal portion it is capacious, but it gradually narrows as it proceeds backwards, so that it becomes of very much diminished calibre before arriving at the cardiac extremity; of the stomach, where its coats are markedly strong and thick. All the internal membranal lining of the mouth, the pharynx, and the oesophageal tube, down as far as a point opposite the base of the heart, is normally, in the living Heloderma, of a deep black colour, due to an abundant deposit of pigment in the mucous coat lining the parts in question. Below this, however, such colouring entirely disappears, and the internal coat again assumes its more natural tints. Strong, longitudinal rugae already make their appearance here in the posterior fourth of the oesophagus, and these are continued on into the stomach; we also observe that both the circular and longitudinal muscular fibres of this division of the alimentary tract are well-developed as we come to examine its posterior portion. The Stomach, in a full-grown lizard of this species, measures for its greatest length about 9'2 centimetres and at its greatest width about 2*5 centimetres ; this last measurement is taken at the junction of the middle and the pyloric thirds. The anterior or the somewhat shorter border of the organ exhibits one general concave curvature that may be divided into two lesser and similar ones; the posterior and at the same time the longer border exhibits one general convex curvature for its length. Muscular fibres can plainly be made out upon its external surface running in the longitudinal direction adown its cardiac moiety, they being continuous with those of the oesophagus. At the cardiac end of this gastric pouch the oesophageal tube gradually widens as it merges into it, and in reality no proper line can be drawn to define any exact cardiac orifice ; but this does not strictly apply to the pyloric extremity, for there we can very well define the line of union between gut and stomach. Upon opening the latter, we have presented us for our examination the abundant longitudinal rugae of the cardiac half of the sac, while these are generally reduced to two for the mucous lining of the pyloric moiety, and from these two well-defined ridges strong transverse rugoe branch off. These are continued to the " pyloric valve," an annular muco-muscular ridge which constricts the orifice of this end of the stomach where it joins the small intestine. A lens of moderate power will discover to us the gastric alveoli, but they are not. conspicuous, and it would require a good microscope to make out such structures as gastric follicles and peptic glands if they exist in the internal mucous coat of this lizard, as they no doubt do. The entire intestine, in this same specimen, measured from the stomach to the border of the anus, has a length of 40 centimetres, and it presents the usual Lacertilian characters1. The duodenal por- 1 In the specimen under examination a complete invagination of the small intestine existed, which, however, did not in any way involve the duodenum, although it was very extensive below that point. The gut was but slightly thickened from the inflammatory process, and by gentle traction the inslipped or upper portion was easily pulled out, and this I did, wondering all the time whether such an accident often took place in lizards. |