84 



Conservation Department 



stellate ohromatopliores over intestine, and behind vent an uneven 

 double line of c. 12 intersprinkled with smaller ones to tip of tail. 



Fig. 8. — Leucichthys artedi, 12.5 millimeters 



12.5 mm. stage. Fig. 8. Total length 12.5 mm; length to vent 

 8.5 mm; greatest depth 1.6 mm; diameter of eye 1.0 mm; 

 myomeres 38 to vent, 19 behind. Immediately after preceding 

 stage yolk beginning to shrink, and at this stage represented by 

 only a fragment showing yellowish through the body wall. 

 Embryonic marginal fm unchanged ; pectorals enlarged ; notochord 

 turning upward ver}^ slightly. The linear chromatophores on 

 underside of yolk sac now more numerous, giving a ''pin feather" 

 effect, and those on sides of sac increased greatly in size and 

 remarkably stellate ; others unchanged. Head less blunt than 

 before; lower jaw slightly shorter. All specimens examined thus 

 far with heavy dorsal pigment on head and beginning of dorsal 

 ridge, then a break until shortly before vent during which chroma- 

 tophores are quite sparsely distributed, thence closer together, 

 more numerous, and forming a verv distinct band. 



Fig. 9. — Leucichthys artedi^ 14.5 millimeters 



14. .5 mm., stage. Fig. 9. Total length 14.5 mm ; length to vent 

 10.6 mm; length of head 2.5 mm; greatest depth (head) 1.92 mm; 

 diameter of eye 1.25 mm; maxillary 1.1 mm. Embryonic marginal 

 fin broken dorsally at former notch and well separated from pos- 

 terior portion ; no rays evident but some concentration in the 

 anterior portion indicating later position of basal elements ; ven- 

 trally marginal fin much reduced; caudal becoming heterocereal by 

 dorsal extension of notochord, outer contour very slightl}^ notched, 

 and few rays suggested ventrally; no ventrals in this specimen 

 althongh iH'ginning in another specimen only 13.2 mm. long. 

 Tfejul iiioic poinlcd; iiiaxilhiry to middle of pupil. Chromato])hores 

 increasing gicatly on top of head; donble dorsal series with 3 or 4 

 lines of smaller oiu's between; more on sides of body and on 

 dorsal surface of intestine, both surface and subsurface; few 

 extending on to caudal. 



