478 



Naclidruck verboten. 



The Branchial, Pseudobranchial and Carotid Arteries 

 in Heptanchus (Notidanus) cinereus. 



By Edward Phelps Allis, jr., Menton. 



With 2 Figures. 



In a recent work on Chamydoselachus anguineus (Allis, 1911), 

 I found the afferent arteries in the hyoidean and branchial arches 

 of either side all connected, in pairs, by dorsal and ventral commissural 

 vessels, these vessels forming a series of loops which encircled the 

 dorsal and ventral ends of each gill cleft. This condition not having 

 been described in any other fish, so far as I could find, and wishing 

 to know if it was peculiar to Chlamydoselachus, I asked the Naples 

 Zoological Station to procure for me, if possible, heads of both Hept- 

 anchus and Hexanchus. Hexanchus they were unable to procure, 

 but two heads of Heptanchus cinereus were sent me in due time. 

 One of these heads was quite fresh and suitable for the dissections 

 proposed, while the other w^as of but little value excepting for control. 

 The heads w^ere given to my assistant, Mr. John Henry, for dissection, 

 and as the arteries in this fish have never been described a complete 

 dissection of the cranial vessels was made and they are here described. 

 The method employed was to inject with ordinary ink or carmine 

 fluid, and to repeat the injections as the dissections progressed. This 

 method gives excellent results for the larger vessels, but it is evident 

 that many of the smaller vessels may be overlooked. 



In my one good specimen of this fish the afferent hyoidean and 

 six afferent branchial arteries, on either side, all arise separately and 

 independently from the truncus arteriosus, the first and second 

 afferent branchial arteries arising somewhat farther apart than the 

 other arteries do. The hyoidean and first branchial arteries are 

 connected, near their ventral ends, hj a small commissural vessel 

 which forms a loop around the ventral end of the first gill cleft, and 

 the fifth and sixth branchial arteries are connected by a similar loop. 

 The remaining afferent arteries are not so connected, but from the 

 second, third, fourth and fifth branchial arteries a delicate branch 



