REPORT ON THE DEEP-SEA FISHES. 245 



The abdominal organs are in all our specimens much decomposed, so that the 

 following observations only could be made : — 



The intestinal tract above the pylorus is distinguished from the remainder by its 

 deep black colour, which is spread over the interior as well as the exterior surfaces, 

 and in fact through the whole tissue of the oesophagus and stomach. The cardiac 

 portion of the oesophagus is beset with rather long villii which are replaced by 

 longitudinal folds in the stomach. Form of the stomach siphonal. Five pyloric 

 appendages of moderate length. The remainder of the intestine very little convoluted 

 and narrow. Liver not divided into lobes. Gall-bladder with rather fii-m walls. 



The air-bladder is of an oval shape, and occupies the posterior half of the abdominal 

 cavity ; anteriorly it is divided into two short cornua. Its peritoneal coating is very 

 firm ; its proper membrane consists of a thick pearl-coloured substance, the inside of 

 which is coated with a delicate vascular membrane which can easily be detached from 

 the pearly portion. In one of the cornua this membrane passes into a pair of thick 

 muscle-like pads, but the specimen is in too bad a condition to ascertain their nature. 

 A pneumatic duct can be traced for a short distance from the end of the left comu, but 

 is soon lost, and does not appear to reach the oesojihagus. The kidneys are confluent 

 into one short body, the foremost portion of which extends into the abdominal cavity 

 behind the thick peritoneal covering, whilst the larger portion is situated between the 

 muscles of the tail. 



The osseous framework of this fish is so much wanting in the characteristic 

 peculiai'ities of bathybial fishes, as to throw serious doubts upon the statement that 

 this species at least of Notacanthus lives at a great dej^th. The ossifications of the 

 skuU (PI. LX. figs. 9-15) are very firm, so that the sutures betw^een some of the cranial 

 bones are obscure or have disappeared altogether. The cranium proper (figs. 10, 11, 

 12, 14) consists of the short and compressed brain-capsule, which is connected with the 

 small and narrow facial portion by the extremely narrow frontal and basal bones ; 

 the orbit being a wide suboval vacuity, bordered in front by a vertical strip of the 

 ethmoidal cartilage. The upper surface of the brain-capsule is smooth and rather 

 convex ; the sides slope inwards, with an uneven surface crossed by two subparallel 

 ridges in the epiotic region, the articular facet for the hyomandibular being below the 

 lower ridge ; the basis cranii shows a projecting V-like ridge, open behind (fig. 12); 

 the occipital region (fig. 14) is subvertical, bordered above with a slight ridge, with 

 a low swelling above the foramen occipitale, and another on each side ; the orbito- 

 sphenoid region is entirely membranous. 



The primordial cartilage has entii-ely disappeared in this part of the skull, and 

 owing to the obscurity of the sutures the outlines of the following bones only can be 

 distinguished. The basioccipital (figs. 12, 14, ho) is large, with a rather shallow 



