. Fresh-water biology. Freshwater biology. Eye and ocellus near margin. Ros- trum acute. Eleven to twelve groups of fine spinules on post-abdomen. Length, 9, to mm.; $ , to mm. Common everywhere, among weeds, in relatively open water; not in muddy pools. Fig. 1121. Acroperus harpae. 0,J MM. 131 (130) Dorsal and ventral margins nearly straight. Acroperus angustatus Sars 1863. Crest larger than in A. harpae; eye and ocellus removed from margin and rostnmi obtuse. Length, 2, to mm.; J, mm. Common in similar situations to preced- ing species. Transition forms between these species
. Fresh-water biology. Freshwater biology. Eye and ocellus near margin. Ros- trum acute. Eleven to twelve groups of fine spinules on post-abdomen. Length, 9, to mm.; $ , to mm. Common everywhere, among weeds, in relatively open water; not in muddy pools. Fig. 1121. Acroperus harpae. 0,J MM. 131 (130) Dorsal and ventral margins nearly straight. Acroperus angustatus Sars 1863. Crest larger than in A. harpae; eye and ocellus removed from margin and rostnmi obtuse. Length, 2, to mm.; J, mm. Common in similar situations to preced- ing species. Transition forms between these species may be found and very probably they should be united. Fig. 1122. Acropenis angustatus. MM. I ' r32 (124, 129) No crest i33 133 (134) Valves not tumid; post-abdomen broad. Alonopsis Sars 1862 . 133a. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ward, Henry Baldwin, 1865-1945; Whipple, George Chandler, 1866-1924. joint author. New York, John Wiley & sons, inc. ; [etc. ,etc. ]
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
