A treatise on zoology . the anus (Fig. 355). In the malethe ducts are more specialised(Budgett [G8]). The testis sacpasses directly into a tube leadingbackwards to open into the urinarysinus, formed by^ the junction ofthe mesonephric ducts (Fig. 356,C and F). The spermatozoa passout through the median urino-genital pore without entering thekidney. This separation of thevas deferens from the mesoiiephrosis probaljly secondary, and may beconsidered to have been broughtabout l)y the same gradual processas in the Dipnoi (p. 253). Thefreeing of the vas deferens fromthe mesonephros, however, is note
A treatise on zoology . the anus (Fig. 355). In the malethe ducts are more specialised(Budgett [G8]). The testis sacpasses directly into a tube leadingbackwards to open into the urinarysinus, formed by^ the junction ofthe mesonephric ducts (Fig. 356,C and F). The spermatozoa passout through the median urino-genital pore without entering thekidney. This separation of thevas deferens from the mesoiiephrosis probaljly secondary, and may beconsidered to have been broughtabout l)y the same gradual processas in the Dipnoi (p. 253). Thefreeing of the vas deferens fromthe mesonephros, however, is notevidence of any close relationshipwith the Dipnoi, since it is foundto have taken place independentlyin the Teleostei (p. 366) and inthe Amphibia (some Anura). Owing to the presence of lobatepaired fins, of paired gulars, ofrhomboid scales, and of an out-wardly diphycereal tail, and to aconsiderable similarity in the dis-position of the roofing cranial Alimentary canal of A, ; and boneS, Huxley placed the Poly. B, (From Gegenbaur, Vergl. ... , . ?? •, ^„r.^ Anat.) «p, caecum ; -?.]>, pyloric caeca ; rfc, pterini Ul hlS SUb-Ordcr CrOSSO- hepatic duct; m, spiral valvp; r, stomacli. 1 .,o L J i » living with the fossil genera, theresemblance of the paired fins is merely superficial, that of thecranial bones only general; the tail is probably secondarily sym- POLYPTERINI 299 metrical, and the scales are of very different structure. Of allthis evidence the presence of paired gulars is the only item f g / ds. vel.
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