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posterior und Aorta", DoHRN says: "In der That findet es sich auch 

 bei allen Torpedo-Embryonen, die eine Größe von weniger als 12 mm 

 erreicht haben, und unterscheidet sich nur dadurch von dem gleich- 

 namigen Theil bei den Haien, daß keine Spur irgendwelcher Verte- 

 bralarterien von ihm ausgeht. Bei Embryonen von 12 mm und mehr 

 ist dagegen nichts mehr von diesem Verbindungsstück zu bemerken." 

 This Statement, literally interpreted, would evidently mean that in 

 Torpedo embryos of less than 12 mm in length the arteries here under 

 consideration are exactly similar to those in selachian embryos with 

 the single exception of the absence of certain vertebral arteries, and 

 that there is accordingly in Torpedo embryos, as is shown in Dohrn's 

 (1885) figures of selachian embryos, a posthyoidean section of the 

 lateral dorsal aorta that connects, posteriorly, with the anterior end 

 of a preglossopharyngeus section of the median dorsal aorta. This 

 section of the aortal vessel, in selachian embryos older than those 

 figured by Dohrn, is said by him to undergo great relative reduction, 

 but to persist even in the adult, while in Torpedo embryos older than 

 those 12mm in length it wholly aborts; and it is implied that this is 

 the only difference in the vessels here under consideration in the adults 

 of these two suborders of fishes. But if this were actually the case, 

 it is evident that, in the adult ray, the posterior portion of the circulus 

 cephaUcus, on either side, would necessarily be formed by the epi- 

 branchial portion of the efferent glosspoharyngeus artery and by that 

 artery alone, and that to further produce the conditions found in the 

 adult ray the efferent glossopharyngeus and first vagus arteries would 

 have to fuse throughout the longer part of their epibranchial length, 

 this fusion taking place in late embryonic, if not even in larval stages. 

 This is certainly wholly improbable, from a consideration simply of 

 the conditions in other fishes, and it is moreover not at all in accord 

 with Eaffaele's (1892) descriptions and figures of younger stages 

 of Torpedo embryos than those described by Dohrn, in which embryos 

 Dohrn's "Verbindungsstück", called by Eaffaele "la radice aortica 

 di Hyrtl", is said to be represented wholly by that portion of the 

 lateral dorsal aorta that lies between the hyoidean and first branchial 

 afferent arteries ; and in which descriptions and figures, also, the lateral 

 dorsal aortae of opposite sides are shown wholly separate and independent 

 to a point somewhat posterior to the second branchial efferent arteries 

 instead of being fused, as shown in Dohrn's figures of selachian 

 embryos, to a point somewhat anterior to the first branchial efferent 



