sTrmii'.oN-i-isiiKs. 



1053 



the liiteral mitrrior iiiar.iiili of tlie vi^iilif lolir; iiiiil the 

 I'lill-iliifl {i/ucfiis cItnlcdocliKs coiiNinniis] opens on llir 

 riaiit side of ihc iibove-inentioiu-d paiici'cMtic oi'iticcs. 

 Tlic spleen (/), .-ilioilt lo' ,, cm. lont:' and .">'., em. hl'oad, 

 is pointed l)eliind and forked, beina; divided from in 

 front, tliroii.iiiiout tlie iireater' part of its lentrtli, into 

 two anteriorl\' jiointed lobes, tlie 1o\\<t of wliieh lies 

 und<'r and to the left of the alu)\ c-mentioned tirsl erook 

 1)1' the stoliiiieh, behinil and pl-ojet'tiui;' a little \\a\- o\cr 

 the paiu-reas, while the other lobe is laid to the right 

 of the mesenterial fold joining the stomach to the intes- 

 liiu'. TIh' testes {ts and til) of the jirosent speeimen, 

 whieh was taken in the middle of duh-, are \-er\ tnmid, 

 ;nid had ne.ai'K' .attained their annu.al ripeness. They 

 extend throughout the greater part of the length of the 

 ,-d)doniin.al e,a\it\-, the left being, howexci', longei- ih.an 

 the right, 'riironghout their length tlK'V are divided 

 into iri'egular lolies by transverse ineisions and slud- 

 Idwer consti'ietions. The length of the loft testis (/.s) is 

 ')A cm., its greatest breadth 7' o cm., .-iiid its greatest 

 thickness 4 cm. The corresponding ilimensions of the 

 right testis (f(l) are respectively 49 cm., (i cm., and o 

 cm. So oblique is the relative po.sition of each testis to 

 the other that the hind extremity of the left only ex- 

 tends to a point distant 11 cm. from the anal aperture, 

 a distance whicdi in the ease of the right testis is re- 

 duced to 7 cm." Their outside (facing the wall of the 

 abdominal cavity) is convex, their inside flatter; the 

 former is covered with an extrenielv thin membi-ane, 

 the latter v\itli a thicker contiiniation of the mesorchiinn, 

 the jK'ritoneal membrane that holds eacli testis susj)end- 

 ed partly (in front) from the wall of the abdominal 

 i-avity, parth- (fui'ther back) from the air-bladder. ])artly 

 (behind the air-bladder, which terminates about 19' ^> 

 em. in front of the vent) from the kidneys. Posteriorly 

 tile mesorchium is thickened (* — **), on the left testis 

 for a distance of about 10 cm., on the right for about 

 >i cm. I'x'hind this tliickening tlie testes are free from 

 tlieir siispeiisor\' membrane, the" left only for a very 

 little way, the right for a distance of 6\„ cm. < )n the 

 inside, in front near the middle of thi' breadth or even 

 near the lower, free margin of the testicle, behind 

 near its up])er (suspensory) margin, runs a wide ef- 

 ferent duct (/7/.S- (IrfrrPiist). the radices of which ramify 

 in all iiarts of this side. The efferent duct is skirted 



by a sharp-edged, imiIkm- thin, adipose band, with free 

 margin and in soiiii- places 1 cm. broad, at other 

 points narrower or e\en merging into the uie.sorchium. 

 .\ir blown into the efferent duet spreads jiartly into 

 its ramitieations, parth-, in the hind portion of the 

 testis, into large lacume betweiii the testicular mem- 

 brane and the stroma. Mercurx' injected into the 

 duct peiielr.atcs through canals in the thickened part 

 (* — **) of the mesoi-chium into the kidneys. It is 

 thus evident that the sperma may find egress in this 

 direction and ihiough the ureter; but another ])assage 

 seems also to be afforded. IJolh male and female Stur- 

 geoii-tislies possess peritoneal tunnels, not unlike those 

 we ha\e seen ;d)o\e in female Salmonoids, es]:)eeially 

 in the Smelt and <'apelin. lint here these funnels are 

 developed into inile|ien(leiit ducts {M), distinct from 

 the true organs of genei'ation, denselv ciliated, anil 

 opening behind into the ur<'ter. They are thus full)' 

 homologous with the so-called .}fiiUerian ditcts (ovi- 

 ducts) of the tiaiioids, l.iing-tishes, Selac^hians, and the 

 higher vertebrates. In the males of most vertebrates 

 the\- are more and nioiv reduced, the testes being fui'- 

 nished instead with deferent canals through the pro- 

 iie])hros; but in the Sturgeon-tishes this transformation 

 has not advaiK-ed so fai', the males having as large, 

 as open, and apparentl\- i(uite as functional Miillerian 

 ducts as the females, in the above-mentioned male 

 Sturgeon the iiiiK r (abdominal) aperture (apm) of the 

 left Miillerian duet lies about ;^l' 2 cm., that of the 

 right 32' ^ cm., in front of the anus; and the former 

 duet measures l.i cm. to its jiosterior apertui'e, which 

 opens into the ureter. l"re(|uentlv'', at least in male 

 and female Sturgeons not yet in spawning condition, 

 the last-mentioned .iperture is closed; but to judge 

 bv the perfect development of the .Miillerian ducts in 

 our specimen, it would seem <|uite probable that they 

 may be functional in breeding tisli of both sexes, even 

 if the sperma of the males may also find its way into 

 the ureter b^- another mod(! of passage. 



( )n each side of the anus the Sturgeoii-tish(>s are 

 commonly furnished with a so-called ahcJomincd pore', 

 an ajierture by means of which the abdominal cavity 

 communicates with the surrounding water. It is often 

 wanting, however, as in the s])ecimeii just described. 

 Its function is somewhiit doulitful, though probably 



° In another Sturgeon tlie rel.itinns were reversed; tlie left testis exlemled fiirllii 

 '■ Cf. .luN-GERSEN, Bidr. Kuiuhk. A'flH«jn/. Udv.. Dis,,. Kbl.vi, 188!>. |.. KU. 

 •• Cf. Wehku. Mcirpliol. .liilirl... ltd XII (IKSCi). p. :!6t;. 



biiekward direetion. tli:in the right. 



