256 



deutlich von dem Hauptstück ab. Der Hals ist sehr kurz. Ein kurzes 

 Endstück ließ sich oft deutlich erkennen. 



Aus obigem geht hervor, daß die reifen Spermien von Phoca keine 

 Besonderheiten darbieten und eine große Aehnlichkeit mit den Samen- 

 körpern der Carnivoren, insbesondere des Haushundes, besitzen. 



Nachdruck verboten. 



The pseudobranchial and carotid Arteries in Ameiurus. 



By Edward Phelps Allis, Jr. 

 With one Figure. 



McKenzie ('84) has described the blood-vascular system of 

 Ameiurus Catus (nebulosus?) but his description of the prebranchial 

 arteries is incomplete in certain important particulars, at least for 

 larvae (of Ameiurus nebulosus): this statement being based on the 

 examination of a single series of transverse sections of a larva (of the 

 latter species) about 25 mm in length. 



According to McKenzie's descriptions of the adult, the truncus 

 arteriosus ends anteriorly with the afferent arteries sent to the first 

 branchial arches. I however find, in my larva, a small median artery, 

 not described by McKenzie, that has its origin from the truncus 

 slightly posterior to the afferent arteries to the first branchial arches, 

 and this little artery certainly represents a prebranchial portion of the 

 truncus. It runs at first downward, and then forward between two 

 separate and more or less complete plates of bone that form the 

 vertical part of the urohyal (Mc Murrich '84), and at the anterior end 

 of that bone separates into two parts. These two parts turn one to 

 the right and the other to the left, and then backward and outward 

 along the dorso-internal surface of the corresponding hyoideus muscle, 

 continuing in that position into the gill cover. These two parts of 

 the small artery thus each has a course and distribution similar to 

 that of the persisting remnant of the afferent hyoidean artery in Amia 

 (Allis '00), and they quite unquestionably represent that artery. 



The arteria hyoidea, or afferent mandibular artery has acquired 

 a secondary connection with the ventral end of the efferent artery of 

 the first branchial arch, as McKenzie describes without naming the 

 artery, and has the general course given by him as far as the upper 

 end of the ceratohyal. Beyond that point I could not satisfactorily 

 trace it, but it doubtless has the distribution described by him. It 



