:■:l..\s\l^l!K.\^■(*II^ 



1075 



sac, Init lieiids t'orwnrd in a ]i\l(ii'ii' pari (toy), l-'niin 

 the ii\'liiriis the (Iui.iiKmiuui runs straiuiit hark, and 

 passes into tlu' spii'al intestine {//), whieli is eontinned 

 |i\- the slmrt i-eetnni. The niueims nuMuhrane dl' the 

 iiiti'stiiial canal differs in the vai'ious seetions much as 

 in titc case of tlie ('lionch'osteans. In the (csopiiaf2:iis 

 it tofins hmyitudinal iiv. in additii)n, ti-ans\-ei'se tuhis, 

 or is reticulated; or it ni;iy i)e studded with more or 

 less hard ]iapilhi', pointed excrescences, in considerahle 

 innnher. The nnieoiis niemhrane of the stomach is 

 iisiialK' coursed liv stroniiK' de\eloped (hut t'rw) lon,i;i- 

 tudinal folds. The ijvloric part, where there are also 

 longitudinal folds of the mucous memlirane, is some- 

 times without internal limits, but sometimes hounded, 

 hoth at the beginning and end, by an annular \al\'e". 

 As we ha\(' remarked abo\e (p. 1().")'2, note /*), the 

 spiral inti'stine is usua.lh' regarded at the present day 

 as a section of the duodenum. The spiral fold in its 

 interior is ver\' highly developed in the genei'ality of 

 the Klasmobranchs\ with reticulated mucous nn'inbrane 

 and with Transverse ridges on most of the coils. The 

 rectum is short, and its nnicous membrane smooth. 



The ]i\er (tig. oOl, c) is large and oily, usually 

 con.sisting in the Sharks of two lobes, in the Ka.vs of 

 three. The gall-l>ladder lies free, or is embedded in the 

 liver. The spleen (.r) lies at the posterior part of the 

 stomach. To the riglit thereof (vertically below /' in 

 the figure) lies the pancreas, \vhich is usualh' of less 

 volume. Into the beginning of the rectum there opens 

 a digitiform gland (/), which was first remarked bv 

 MoNKO' under the name of vermiform appendage or 

 coecal sac', but whose glandular, botryoid structure, 

 around a central efferent duct, was first (dearly de- 

 scribed by LEYDir,'. 



There is no air-bladder. The kidneys (fig. 301,;;?) 

 are situated as in the Teleosts. They taper in front 

 and expand liehind, sometimes so greatly that they 

 seem to be confluent. Their general shape adapts itself 



to the external form of the liod\'. Thus the)' are 

 elongate(l in the Sharks, broader and shorter in the 

 Rays. 'I'he ui'iiiar\- bladder is usually double, forming 

 a dilatation of each ureter. 'Ihe anterior part of each 



l''i!; 



:!0i. 



Alnln 



;il visi-ern ut a iii.-ilc Sliarlc. After KYMElt-.JoXE5. 



(7, lie:irl; 0, gill-openings; c, c, a, lobes of the liver, tlie left removed, 

 the liiiilrlle (lutiuliis iSpiei/elii) and riglit retained; d, oesophagus, pass- 

 iiif;- into tlie sfoiiiaeli (e). wliic-li is eontinned by the dnodenmn (/), 

 into wliiib the gall-duet (</) opens; //, spiral intestine; i, glandnla 

 rclt'oaniih's; k, urogenital cloaca; I, pterygopodiuni ; m, left kidney; 

 n, left testi.s; o, uas deferens; p, dilatation of the Kas deferens (vesi- 

 riilii xeminali.f); r, urogenital [lapilla; .v, ahdoniiiial (|ieritonenl) pores; 

 .,; spleen. 



" In the Basking Shark Blainville (I. c, p. lOtJ, pi. (!, tig. •>. O) hence gave to this section Ihe iiuiiie of the third sturiiuch. In 

 the Picked Dog-fish I find no valve, either between the stoniaeh and the pyloric part or between the latter and the diiodeniini. 



'' In a Picked Dog-tish I find 14 coils; Kroyer found 1(1 or 17. The last coil terminates in a broad, labiated fold. In several 

 Sharks, however, the spiral fold is less developed. In Alopias vulpcs and V'ircharias (jlauciis it is described as very short. In Thalassorhi- 

 Hus viilpecnla and Zygwna tudes no stair-like coils arc formed along the inside of the intestine, but a long and broad membrane curves in 

 comet-shaped folds, one within the other, and lies like a packet within the intestine, with only one margin attached to the wall thereof. \t 

 Ihe free margin of this membrane runs, according to Duvernoy (Ann. Sc. Nat., Zool., 2 ser., tome III. p. 274, pi. 10 and 11), a power- 

 fully muscular venal trunk (^vena niesenterica), which is continued by the vena porta and impels ihe blood and chyle into the latter. 



' ■Strui't. Physiol. Fish., Edinb. 1785, PI. II, 8; I'l. 111. /•.'; PI. XI, D; PI. XVIII, 16; PI. XIX, 14. 



' /iursa ctoaae, Retz., Obs. Anat. Vhondropt.. \i. 24. alundula retroanalis, Costa, Fna Regn. Nap., Chimeridei (1852), p. .36, 

 lav. II, tig. 1 , y. 



■" Beitr. mikr. Anat., Entwickcl. llaien nnd Rnrhen (lS.i2), p. M, § .-'.S. 



