. Notes on the North American ganoids [microform] : Amia, Lepidosteus, Acipenser, and Polyodon, with three plates. Ganoidei; Fishes; Ganoide; Poissons. ^Jk .*â. B. NATURAL HISTORY. 157 rnordial fin ex- This fin is quite hited by very I incline sJightJy I tliis specimen, fger specimens py. whence we P'ery acute. otonward incli. either nearly r. special altera- opposite each 'tejior to the funding parts n of pigment y the portion arge rays, or >rdial fin, are 'd hardly be larger speci- jj ^cemus; but Undina and h6reaflter. ^oung Lepi. an the rest space are downward le body i
. Notes on the North American ganoids [microform] : Amia, Lepidosteus, Acipenser, and Polyodon, with three plates. Ganoidei; Fishes; Ganoide; Poissons. ^Jk .*â. B. NATURAL HISTORY. 157 rnordial fin ex- This fin is quite hited by very I incline sJightJy I tliis specimen, fger specimens py. whence we P'ery acute. otonward incli. either nearly r. special altera- opposite each 'tejior to the funding parts n of pigment y the portion arge rays, or >rdial fin, are 'd hardly be larger speci- jj ^cemus; but Undina and h6reaflter. ^oung Lepi. an the rest space are downward le body is ""gination. the tail of probably ted. â Dgr skate as â¢l«e before The spociri. ; above described, represents, so far as,I am aware, the earliest known stage of Lepidoateus. But there can be no doubt that at a still earlier stage the tail was simple and undiffer- entiated like that of Amphioxus. A second very small specimen is no longer than the one above described, but seems to be more developed. It is darker colored; the belly being almost black while the upper half of the body is browjiiiJh. The four median flns are indicated by decided though irregular blotches, and the rays of the infra-caudal are more dis- tinct. White longitudinal elevations show where the ventral fins ( Ve) are about to appear. The difference in the color of these two smallest specimens is very marked. The white one is apparently the younger although a trifle the longer. But it cannot be determined at present that the color is developed only after the attainment of a certain size or stage of growth. The specimen next figured (Fig. 2) presents the following fea- tures. Its length is 23"'"'- Its colors are darker than the one first described, but less decided than in the second small specimen re- ferred to. The ventral flns ( Ve) are little white buds opposite the anterior extremity of the primordial fin (1). This latter has changed but little. It seems rather thinner and its b
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectfishes, bookyear1876
