SIIKATKISII. 



699 



into till' siiKill iiitestiiu', often in several small (•ui-vi's,iil)(>\e 

 and behind the stomach. Here the intestine ai;aiii IhikIs 

 forwards, below and to the left of the stomacii, to ationt 

 a line with the |)\'lorns, then returns in a sliarji enr\(,', 

 and proceeds to the vent. The liver is large, tiioiigh 

 its length varies: the left lobe is the longer, extends to 

 about a line with the bottom of the stomach, sometimes 

 not ([uite so far, sometimes much farther, and is divided 

 at the tip into two secondary lobes of varying length". 

 The gall-bladder, which lies between the duodenum and 

 the anterior part of the left lobe of the liver is saccate 

 and lai'ge''. The pancreas' lies nearer the duodeinim, 

 in the shape of a horse-shoe with the prongs directed 

 forwards and surrounding the gall-duct. The spleen is 

 situated aliove the stomach, between this organ and the 

 air-bladder, to the left of the iirst coil of the intestine 

 and sometimes entirely in fnjnt of, sometimes half in 

 front of and half behind and above the anterior angle 

 of the last coil of the intestine. It is rounded (ellip- 

 tical) and flattened'. The structure of the large air- 

 bladder is mentioned above''. The under surface of its 

 postei'ior division is furnished with a longitudinal groove. 



and twisted; and wiiliin tiie angle of the Itend the base 

 of the descending blade forms a free margin, which, when 

 the bone is in its natur.al position, lies as a continuation 

 of the upper margin ol' a lateral groove on the body of 

 the vertebra. .Vs only the third (hindmost) of the coa- 

 lescent vertebra^ is furnished with ribs, the so-called 

 mallvKs thus corresponds to a ril) of the middle ver- 

 tebra (the third al)dominal vertebra), '^fhe malleus co- 

 heres at its iiuii'r antei'ior corner with the vertical, flat 

 incus', which should thus correspond (if this homology 

 with The ribs should I'eeeive the corroboration it still 

 requires fi-oiii tiie history of d(>velopment) to a rib 

 of the foremost of the coalescent vertebra' (the second 

 abdominal vertebra). The first abdominal vertebra, which 

 in the Sheatflsh is separated both from the following 

 vertebnu and the occipital bone, is without either trans- 

 verse process or neural ai'eli, unless these be represented 

 on each side by the angular stapes, which is united hx 

 ligaments to the subjacent incus, and In* the flat, 

 but oblong chiustrum, wiiich lies above this point, is 

 also united to the stapes, and covers the atrium sinus 

 impaii>i on this side of the body. This atrium, which 



at the anterior end of which the pneumatic duct de- } lies beside the spinal cord, is a lateral extension of the 



scends into the cesophagus. The anterior end of the air- 

 bladder is attached parti}- to the lower surface of the 

 tip of the foremost ti-ansverse processes (belonging to 

 the second abdominal vertebra), partly to the anterior 

 part of the side of the large vertebra which, as we have 

 mentioned above, is produced by the coalescence of the 

 original second, third, and fourth vertebi'a?. Within the 

 latter fastening of the air-bladder lies the descending 

 blade of tlie hindmost and largest, so-called acoustic 

 bone (malleus), which is loosely folded in beside the 

 large, composite vertelira. The second blade of this 

 acoustic bone lies horizontally, pointing in a forward 

 direction, at right angles to the descending blade, and 

 glides along the under surface of the base of the flrst 

 transverse process. This acoustic bone is tluis both bent 



sinus impar situated in the occipital bone, a mem- 

 branous, saccate extension of the cerebral membrane 

 that lines the labyi'inth. The anterior end of this sinus 

 is furnished in the Cai-p-flshes'' — and jjrobably here as 

 well'' — with a connecting duct between the sacculi of 

 the labyrinth. The air-bladder is thus connected by 

 means of the acoustic bones, not indeed immediately 

 vvith the true hearing-apparatus, but with the 13'mphatic, 

 subdural chamber that surrounds the latter. ^Modern 

 scientists have therefore adopted the opinion' flrst main- 

 tained by Hasse', and regard this conne.xion less as a 

 conductor of sound than as a barometrical apparatus 

 which conveys to the consciousness of these flshes a sense 

 of the varying atmospheric pressure to which their air- 

 bladder is exposed at different moments. 



" In the above-mentioneil specimen the length of the left h'be of the liver is 36' , cm. ami its greatest hrendth nearly 8 cm. The 

 length of the right lobe is li'/j cm., its breadth nearly 5 cm. 



'' In the specimen just mentioned the gall-bladder is about 14 cm. long and, when collapsed, about 6' ., em. broad. 



' The length of this gland from the middle of the round posterit.r margin to the end of one of tlie prongs is (in the same speci- 

 men) about equal to the breadth of the gall-bladder. 



'' In the same specimen the spleen is 11 cm. long, 5 em. broad, and about 8' ., mm. thick. 



^ In the same specimen the air-bladder is 25' 2 cm. long and rather more than il cm. broad. In a female 575 mm. long it is 89 

 mm. long and 46 mm. broad. 



•^ Cf. Weber, De Aure et Aiidilii Huininis el Aniiaaliuiii. tab. V, fig. 30. 



" Cf. NusBAUM, Zoologischcr Anzeiger, 1881, p. 553. 



* Cf. Retzius, Das Gehdrorgan tier Wirbtlthiere, I, p. 77. taf. XIII, tig. 1, si. 



• Cf. S.\GEMEHL, Morphol. Jahrbuch, X (1884), p. 14. 

 ■' Anatomisclie Studien, No. XIV, p. 596. 



