. Fresh-water biology. Freshwater biology. 25 (24) Seven (rarely fewer) large spines in two widely separated transverse rows Chaetonolus spinulosus Stokes 1887. Length to mm. Usually four large spines in anterior row and three in posterior. Some may be suppressed (or lost?), leav- ing three in front and only one in the center behind. Spines of anterior row distinctly longer. Egg mm. long, covered on one side with short hairs. The embryo escapes in thirty hours and thirty hours later the young individual shows an ovarian egg in which the nucleus becomes conspicuous six hours
. Fresh-water biology. Freshwater biology. 25 (24) Seven (rarely fewer) large spines in two widely separated transverse rows Chaetonolus spinulosus Stokes 1887. Length to mm. Usually four large spines in anterior row and three in posterior. Some may be suppressed (or lost?), leav- ing three in front and only one in the center behind. Spines of anterior row distinctly longer. Egg mm. long, covered on one side with short hairs. The embryo escapes in thirty hours and thirty hours later the young individual shows an ovarian egg in which the nucleus becomes conspicuous six hours later. Fig. 975. Chaetonotus spinulosus m ioTsaXwK-w. X 665. (After Stokes.) 26 (21) Spines present on head and neck much smaller than those on body 27 27 (28, 29) Four transverse rows of large dorsal spines on posterior region of body. Also one large lateral spine on each side at caudal process Chaetonotus acanthophorus Stokes 1887. Length mm. Head and neck covered with short spines. Large spines on body in four cross rows of five each, not alternating so that they appear also as five longitudinal rows of four spines each. The last lateral spine at the base of the caudal process is large and much like those in the dorsal rows. Trenton, New Jersey. Fig. 976. Chaetonotus acanthomorphus in dorsal view. X 415. With dorsal spine. X about 1165. (After Stokes.) 28 (27, 29) One transverse row of large spines just in front of the caudal end of the body Chaetonotus spinifer Stokes 1887. Length mm. Back and sides covered by rounded imbricated scales, each with stout recurved spine minutely furcate at tip. The four spines in a single series immediately in front of the caudal process are much larger and stouter than those on the rest of the body. Egg ornamented with processes varying in length and shape in different specimens. Stokes distinguishes eggs with three separate patterns, respec- tively, , , and o 0793 mm. long. Trenton, New Jersey. Fig. 977. Chaetonolus
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
