2.5 mm. SL as a thickening on the ventral edge of 

 the body immediately anterior to the gut, but the 

 right-side base does not appear until about 3.5 mm. 

 SL. My smallest specimen with pelvic fin rays (left 

 side, and elongate rays) was 3.0 mm. SL. The first 

 right-side fin ray is seen on a 5.3 mm. SL specimen. 

 The three elongate pelvic fin rays on the left side 

 develop simultaneously. They are present on all 

 specimens but two (one with a single fin ray and 

 one with two fin rays) . The fourth left fin ray de- 

 velops at about 5 mm. SL, and the fifth and sixth 

 rays by about 10 mm. SL. Each fully developed 

 pelvic fin has six fin rays. The three elongate fin 

 rays of the left side are thickened and heavier than 

 the other pelvic fin rays and extend posteriorly to 

 about the caudal peduncle; they are often broken. 

 None of the other pelvic fin rays is elongate. The 

 origins of the pelvic fin base are equidistant behind 

 the cleithrum. 



LARVAL SPINATION 



A single sphenotic spine and a series of preoper- 

 cular spines (figs. 3-7) persist throughout the size 

 series of my larval specimens (1.72-14.51 mm. 

 SL) . These spines are smaller but similar in posi- 

 tion and shape to those reported for Syacium 

 by Kyle (1913) and Aboussouan (1968). The 

 sphenotic spine becomes relatively smaller as the 

 larvae grow. The spine is surrounded by concentric 

 rings that are first noted on specimens of about 



4.6 mm. SL. Four to six small sharp spines are 

 present on the preopercular margin ; two or three 

 of these are on the ventral edge, a larger single 

 spine is at the angle, and two more small spines 

 are on the posterior edge. The large spine at the 

 angle of the preopercle thickens, and a spur devel- 

 ops on the upper posterior edge of the spine on 

 larger larvae. These spines do not alter position 

 or shape but become relatively smaller with in- 

 creasing size of the larvae. The sphenotic and 

 preopercular spines can be traced through the 

 developmental series and are important in identi- 

 fying this group of larvae (figs. 3-7) . 



PIGMENTATION 



Pigment on all of the Theodore N. Gill material 

 is faded, but pigment patterns are readily seen on 

 the fresh Oregon material. In my sample, pig- 

 ment is first seen on a 2.8 mm. SL specimen — a 

 large melanophore over the base of each sphenotic 



spine, and another melanophore on the gular re- 

 gion between the posterior end of the lower jaws 

 and the tip of the cleithrum. The dorsal portion 

 of the swim bladder and the dorsal loop of the gut 

 are heavily pigmented. On a 3.2 mm. SL specimen 

 the melanophores at the bases of the sphenotic 

 spines have faded, but those on the gular region 

 and along the dorsal aspect of the gut remain. 

 Three clusters of melanophores are present on the 

 dorsal edge, and two are on the ventral edge of the 

 body. The anteriormost is on the dorsal edge of 

 the body over the pectoral fin base (there is no 

 corresponding ventral cluster of melanophores). 

 The other two dorsal clusters of melanophores 

 have corresponding ventral clusters. The middle 

 spots are immediately behind the gut region, at 

 about the midpoint of the body (TL), and the 

 posterior spots are slightly anterior to the caudal 

 peduncle (fig. 4). A series of small melanophores 

 can be seen on the ventral edge of the gut between 

 the vent and the anterior portion of the gut cavity. 

 Pigmentation is essentially the same on specimens 

 up to about 4 mm. SL, but the number of melano- 

 phores increases. Specimens between 4 and 5 mm. 

 SL have a large melanophore on each opercle be- 

 hind the eye and another on the median line at the 

 origin of the pelvic fin base. The dorsal portion of 

 the gut has two areas of dark pigment ; the ante- 

 riormost is on the upper half of the swim bladder 

 and the other is above the loop of the intestine. 



At about 5 mm. SL the melanophore on the 

 gular region has disappeared, but additional clus- 

 ters of melanophores have appeared, one dorsal 

 and one ventral, between the middle and posterior- 

 most cluster but nearer the posteriormost cluster. 

 The two new clusters are of equal size and are 

 smaller than those nearest to them. The remaining 

 pigment is similar to that seen on the smaller 

 larvae. Shortly after appearance of the third ven- 

 tral pigment cluster the posteriormost ventral 

 cluster increases in length and becomes longer than 

 its corresponding dorsal area. 



By 7 mm. SL a fifth dorsal cluster has appeared 

 between the first two clusters. Two pigment clus- 

 ters have developed along the lateral septum, cor- 

 responding in position with the two posterior 

 dorsal and ventral clusters. Pigment is present 

 over the entire swim bladder on the left side and 

 absent on the right side. Pigmentation remains 

 essentially the same through the rest of the larval 



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