FISHERY BULLETIN: VOL. 75, NO. 4 



deciduous scales. The "modified cycloid scales" 

 mentioned by Harrisson and Palmer (1968) may 

 have been the dermal tubercles. 



In addition to the tubercle and pore system, Zu 

 and Desmodema agree in two other specialized 

 characters: the body is constricted behind the vent 

 to form an elongated, slender tail, and there is a 

 distinctive prejuvenile which metamorphoses into 

 the juvenile phase. 



In our interpretation, Trachipterus is the most 

 generalized trachipterid genus, with Desmodema 

 and Zu specialized in respect to the characters 

 given above. Desmodema is advanced with respect 

 to Zu in the loss of the lower caudal rays and great 

 elongation of the tail, and probably in the crowd- 

 ing of the pterygiophores before the first neural 

 spine. The significance of the difference in the 

 relationship of the anterior dorsal fin 

 pterygiophores between Trachipterus and Zu on 

 the one hand and Desmodema on the other is dif- 

 ficult to interpret. In Lophotus there is a single 

 rayless pterygiophore before the strongly 

 forward-curved first neural spine, then about 15 

 uncrowded pterygiophores in the wide interspace 

 between the first and second neural spines. The 



figure of Regalecus given by Parker (1886) clearly 

 shows a condition much like that of Desmodema. 

 Although the caudal of Regalecus has been de- 

 scribed as lacking a ventral lobe, we find that two 

 caudal rays are associated with the terminal cen- 

 trum and four with the (ventral) hypural of the 

 first ural centrum. 



Desmodema polystictum (Ogilby) 



Figures 3, 4 



Trachypterus jacksoniensis polystictus Ogilby 

 1897:649; Newcastle, New South Wales, Aus- 

 tralia; holotype, Australian Museum. 



Trachypterus misakiensis Tanaka 1908:52, pi. IV, 

 fig. 2, "shores of Misaki" Japan; holotype, Zool. 

 Inst. University of Tokyo, No. 960. Herre and 

 Herald 1951:318, fig. 3; 6°26'N, 121°35'E. 



Trachypterus deltoideus Clark 1938:180; Rurutu 

 Island, "Australs" (Tubuai Islands); holotype, 

 CAS 5532. 



Desmodema polysticta. Walters 1963:260; 

 28°58'N, 88°18'W; Integumentary system. 

 Fitch 1964:230; in part, see synonymy of D. 



FIGURE 3.— Adults of the species of Desmodema . Upper figure D. polystictum, SIO 68-333, 1,040 mm SL. Lower figure holotype of D. 



lorum, USNM 216726, 1,098 mm SL. 



848 



