788 



Fishery Bulletin 88(4), 1990 



Figure 1 



Outline t)f hagfish {Eptatretus) showing regions and features used 

 in measuring and counting: A-H. total length (TL); A-B. prebran- 

 chial length: B-C, branchial length, including gill apertures (GA); 

 D. external opening of pharyngocutaneous duct (PCD): E, ventral 

 finfold; C-F, trunk length; F. origin of cloaca; F-H, tail length; G, 

 caudal finfold. The linear series of dots represents the prebranehial, 

 branchial, trunk, and cloacal-caudal (tail) slime pores. 



counting and measuring are shown in Figure 1 . Ab- 

 breviations used are given below and identified in Fig- 

 ure 4. 



Figure 2 



Branchial areas of holotypes of (A) Eptatretux mrmnnaugheyi. (B> E.Jrilzi. 

 andCC)^. sinus; (D) neotype of £■. stout ii; (E)E. deani. The dental mus- 

 cle (DM) is the cylindrical mass lying between the rows of gill pouches (GP). 



Abbreviations 



ABA Afferent branchial artery; one of the small 

 blood vessels that lead to each gill pouch from VA 

 or its branches (Fig. 4). 



DM Dental muscle; the firm elongate, cylindrical com- 

 plex of muscles and cartilages that moves the dental 

 plates and sets of cusps during feeding. Posterior 

 portions of DM are shown in Figures 2-4, lying be- 

 tween rows of gill pouches. 



GA Gill (branchial) aperture; external opening of the 

 efferent duct leading from a gill pouch (Fig. 1). 



GP Gill pouch; rounded, serially arranged structures 

 along and posterior to the dental muscle (Fig. 4). 



PCD External opening of the pharyngocutaneous 

 duct; always confluent with the posteriormost left gill 

 aperture in most species of Eptatretus, and much 

 larger than all other apertures (Fig. 1). 



VA Ventral aorta; the portion between the heart 

 (ventricle) and to where it branches to each side of 

 DM (Fig. 4). 





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