Three species of Syaciwm occur in the western 

 North Atlantic. S. papillosimi (Linnaeus, 1758) 

 and S. micrurum, are difficult to separate as juve- 

 niles and can be separated as adults only by the 

 width of the interorbital space. All other meristic 

 and morphometric characters overlap. S. gtmteri 

 Ginsburg, 1933 can usually be separated from the 

 other two species of Syacmm in the western North 

 Atlantic by the number of dorsal and anal fin rays. 

 Syacium papillosum, and S. micrurum rarely have 

 fewer than 85 dorsal fin rays or fewer than 68 anal 

 fin rays, whereas S. gunteri rarely has more than 

 84 dorsal fin rays and more than 67 anal fin rays 

 (Gutherz, 1967). 



Aboussouan's (1968) description of larval S. 

 micrurum (listed as S. guineensis) is of greatest 

 value for workers in the area off Dakar where only 

 one species of Syacium, is known. His paper is val- 

 uable in separating Syacium, larvae from the lar- 

 vae of other genera. 



Aboussouan (1968) implied that Kyle's Cith- 

 arichthys B. (Kyle, 1913; fig. 29) is a Syacium 

 rather than a Cithanchthys^ but I disagree for the 

 following reasons: At this stage of development 

 larvae of Syacium have numerous elongated dor- 

 sal and pelvic fin rays but the known larvae of 

 Oitharichthys have only a few, if any, elongate fin 

 rays ; S. gunteri has fin ray counts similar to those 

 given by Kyle for Oitharichthys^ but our larvae of 

 S. gu/nteri have the heavy preopercular spination 

 and the large sphenotic spine seen on the larvae of 

 the other species of Syacium; the preopercular 

 armature of Syacium is not reduced or blunted 

 until the right side eye has reached the middorsal 

 ridge or is turning onto the left side ; the mouth of 

 Syacium, larvae is larger than that shown by Kyle, 

 and the origin of the dorsal fin is more anterior; 

 the larvae of several species of bothids have pig- 

 ment patterns similar to Oitharichthys B. I believe 

 this specimen probably represents a Oitharichthys 

 or Etropus. 



ParaZichthys sp. and P. olivaceous larvae have 

 been figured and described by Hildebrand and 

 Cable (1930) ; Deubler (1958) ; Chang, Xo, and 

 Sha (1965) ; and Okiyama (1967). These descrip- 

 tions are based on larvae collected off the Atlantic 

 coast of the United States, off Japan, and on lab- 

 oratory-reared specimens. A high degree of simi- 

 larity in the developmental pattern is noted except 



for Okiyama's P. olivaceous, which have longer 

 elongate dorsal fin rays that seem to persist longer 

 than the elongate dorsal fin rays on the larvae 

 described by Chang et al. (1965). Characteristics 

 common for the eggs and larvae of Paralichthys 

 and a discussion of the relation between the mi- 

 grating eye and the anterior portion of the dorsal 

 fin are given by Chang et al. (1965) . 



Hippoglossina ohlonga larvae have been illus- 

 trated and described by Agassiz (1879, listed as 

 Pseudorhomhus ohlongus), Perlmutter (1939), 

 and Miller and Marak (1962, listed as Paralich- 

 thys oilongus). 



Oitharichthys larvae have been figured by Ahl- 

 strom (1965), and Kyle (1913, fig. 29) has illus- 

 trated what is probably a Oitharichthys or 

 Etrop^is. 



Bothus larvae have been illustrated and de- 

 scribed by Kyle (1913), Colton (1961), and Ochiai 

 and Amaoka (1963) among others. These descrip- 

 tions and figures of larvae collected off the Atlantic 

 coast of the United States, the mid-Atlantic re- 

 gion, and off the Japanese coast show a high degree 

 of similarity. All have only one elongate dorsal 

 ray. 



Ohascanopsetta larvae have been illustrated and 

 described by Kyle (1913) and Bruun (1937). Kyle 

 was unable to refer his larva to any known Atlan- 

 tic species, but Bruun placed it in Ohascanopsetta. 



Illustrations and descriptions of larvae in the 

 closely related Scophthalmidae can be found in 

 Smith (1904), Moore (1947), and Bigelow and 

 Schroeder (1953). 



MATERIALS AND METHODS 



The original sampling procedures used on 

 cruises of the FWS (U.S. Fish and Wildlife Serv- 

 ice) vessel Theodore N. Gill were reported by 

 Anderson, Gehringer, and Cohen (1956) and An- 

 derson and Gehringer (1957). 



Additional plankton samples were collected in 

 January and June 1967 on cruises of the FWS 

 vessel Oregon. Plankton and nekton samples were 

 collected in depths of 14.6 to 45.7 m. (8-25 fath.) 

 by 1-m. plankton and nekton nets (1-mm. mesh) 

 and i/^-m. plankton nets (1-mm. and 0.33-mm. 

 mesh), which were towed for 15-minute periods. 



A size series of specimens was cleared and 

 stained by the procedure given by Taylor (1967). 



264 



U.S. FISH AND WILDLIFE SERVICE 



