11. COLLICHTHYS. 313 



d. Adult : skin ; bad state. China. Presented by J. R. Reeves, Esq. 



e. Half-grown. China. 

 /. Young. China. 



g. Half-grown. China. From Dr. Cantor's CoUeetion. 



h. Young. China. From Dr. Cantor's Collection. 



i. Half-grown. China. From the Collection of the East India 



Company. 

 ]c. Half-grown. Chusan, Presented by the East India Company. 

 l~n. Half-grown and yoimg. India. Presented by G. R. Waterhouse, 



Esq. 

 o-q. Adult. From the Haslar Collection. 

 r. Adult female : skeleton : not good state. 

 s. Air-bladder of specimen r. 



Anatomy. — The intestinal tractus does not show any peculiarity. 

 The stomach is a long caecal sac, with thirteen appendages at the py- 

 loric opening ; the intestines form a flexure behind, and another more 

 anteriorly ; the liver has a longer lobe on the left side, and a shorter 

 one on the right. The ovaria are elongate, cuneiform, united at their 

 posterior extremity, and contain a very great number of small ova. 



The air-bladder (6) has an exceedingly delicate and complicated 

 structure: its body is elongate, cuneiform, rather depressed, with 

 pointed posterior extremity ; the membrane is thick and stiflF. At 

 the anterior extremity of the dorsal side, a cordiform impression is 

 visible, corresponding to a cartilaginous heart-shaped plate of the 

 third and fourth vertebrae; to this plate the air-bladder is firmly 

 attached. The air-bladder emits on each side twenty-five cuneiform 

 appendages, contracted at their base, and tapering at the other end; 

 the anterior ones are directed towards the front, but the lateral ones 

 assume a more posterior direction the nearer they are to the posterior 

 extremity of the air-bladder, where they have the appearance of 

 the Cauda equina of the spiual chord. All these appendages or air- 

 vessels soon bifurcate in a dorsal and in a ventral stem ; these stems 

 bifurcate again and again, and either terminate after the first or 

 second bifurcation, or are so far prolonged as to reach the median 

 line of the ventral and dorsal side, anastomosing with the branches 

 of the other side. All these branches are now enveloped in laminae 

 of the peritoneum, forming a dorsal and a ventral sac of a beautiful 

 appearance, which is caused by the regular arrangement of the air- 

 vessels. 



Before describing the detailed relation of these sacs to the different 

 laminae of the peritoneum, I shall give a short vieAv of their situa- 

 tion. The dorsal sac is situated between the air-bladder and the 

 roof of the abdominal cavity ; it is attached to the sides of tlie air- 

 bladder only, and has no connexion at aU with the vertebral column ; 

 it is very thick, and formed by two laminae of the peritoneum, by a 

 thick intermediate stratum of cellular tissue, and by air-vessels. 

 The ventral sac receives in its cavity aU the abdominal intestines 

 — intestinal tractus, liver, ovaria ; and we have here the remarkable 

 fact of an air-hladder not onJi/ oaupylnc/ the dor.sal part of the abdo- 

 minal cavity, but coveriny all its interior surface by a system of air- 



