1. cnoKisocHisMrs. -ii);j 



ciilum is the largest piece of the opercular apparatus ; its i tei-ior 

 limb IS entirely covered by the tympanic, and its angular portion is 

 much produced backwards and provided with a strong ridge ; inter- 

 operculum feeble, situated at the inner side of the prajoperculum ; 

 suboperculum composed of three processes, the posterior of which 

 terminates in a hook-like spine. The basal portion of the operculum is 

 solid ; the margin thin, cartilaginous. Glossohyal rudimentarj' ; bones 

 of the branchial arches thin and rather feeble ; basibranchials absent ; 

 pharjTigeaLs separated, and armed with coarse cardiform teeth. 



The suprascapula and the scapula are simple styliform bones ; the 

 vertical portion of the humerus is as long as the horizontal ; the ulna 

 and radius are shorter than, and very similar to, the carpal bones. 

 The coracoid is well developed, and, as usual, composed of two pieces, 

 the upper of which is not suspended from the humerus, but fixed 

 by a ligament to the hinder margin of the cai-pal bones ; it is a 

 broad lamella dilated posteriorly into the cartilage, which is externally 

 visible ; the lower piece is narrower, and fixed to the extremity of the 

 pubic bone of its side. The pubic bones are united by suture, and 

 form together a heart-shaped disk, the point of which is produced 

 backwards. The anterior portion of the disk is concave, with a bony 

 longitudinal biidge and a feeble transverse ridge. The disk is fixed 

 to the humeral bones by the convex portions of its anterior margin, 

 whilst the convex portions of the lateral margins serve as base for 

 the ventral fins*. The latter are composed of one spine, which is 

 transformed to a broad thin and curved plate hidden below the skin, 

 and apparently of four rays ; but on closer examination we find that 

 the hidden ray has a longitudinal groove anteriorly, in which another 

 thinner ray lies concealed ; this ray is quite free, and not joined to 

 the pubic bone. We are not aware of another example of a similar 

 stnicture in fishes. 



The vertehral column is composed of fourteen abdominal and seven- 

 teen caudal vertebrae, the abdominal portion being rather longer than 

 the caudal. The first vertebra is thrice as broad as long, with its 

 three conical depressions veiy distinct and situated in the same hori- 

 zontal line ; the other vertebra) become more and more compressed 

 posteriorly. The nciu-al and hccmal spines are of moderate length 

 and strength, slightly inclining backwards. The zygapophyses of the 

 abdominal vertebra) are more developed than is usual in this Order, 

 whilst the parapophyscs are entirely absentf. The ribs, which are 

 rather broad and horizontally directed outwards, are joined into the 

 lateral concavity of the vertebra), immediately below the zygapo- 

 physes. The epipleurals are not much less developed than the ril s 

 from the extremities of wliich they are suspended and directed back- 

 wards. We might also consider the ribs as long and detached par- 

 apophyscs, and the epipleurals as the ribs proper. The interneurals 

 and interha)mals are very feeble. 



* Tlic structure of tlie ventral disk has not yet been correctly described. 

 Stannius, for instance (p. 91), denies the presence of the coracoid. The ventral 

 fins have been taken for a detached ))ortion of the pectorals, &c. 



t Stannius, /. c. p. 34 {Cntylis) 



