. Fresh-water biology. Freshwater biology. 664 FRESH-WATER BIOLOGY. Fig. 1013 Estheria morsei, with left valve of shell removed. X Q. ai, first antenna; 02, second antenna; c. carapace; d, cercopods or furcal rami; /, flabella; u, umbone. (After Packard.) The alimentary canal of phyllopods consists of a large mastica- tory and glandular atrium produced by an overhanging labrum c in front of the mouth; this is followed by a buccal cavity, a ver- tical esophagus and a small globular stom- ach within the head; and, behind these, is a long straight intestine which terminates in a short rectum at t
. Fresh-water biology. Freshwater biology. 664 FRESH-WATER BIOLOGY. Fig. 1013 Estheria morsei, with left valve of shell removed. X Q. ai, first antenna; 02, second antenna; c. carapace; d, cercopods or furcal rami; /, flabella; u, umbone. (After Packard.) The alimentary canal of phyllopods consists of a large mastica- tory and glandular atrium produced by an overhanging labrum c in front of the mouth; this is followed by a buccal cavity, a ver- tical esophagus and a small globular stom- ach within the head; and, behind these, is a long straight intestine which terminates in a short rectum at the posterior end of the body. The heart is greatly elongated in the Anostraca, oc- cupying nearly all the trunk-somites, with a pair of ostia opening in each somite. In the Notostraca and Conchostraca it is more restricted — and extends through only three or four segments in the latter. There are no definite blood vessels. A maxiUary gland (consisting of an end-sac, glandular coiled tube, and short terminal duct) serves as an excretory organ in phyllopods. The ladder-like structure of the ventral nerve chain shows the primitive character of the nervous system. After leaving the egg, all American phyllopods begin their development as a free swimming nauplius or metanauplius (Fig. 1014). Some differences exist even in closely allied forms in regard to the stage of development reached at hatching. The larvae of the Notostraca and Anos- traca are typical metanauplei at the time of hatching, with an oval body that shows the beginning of several trunk-somites posteriorly and sometimes the rudiments of their appendages. The first antennae are well developed but uniramous, the second antennae have a movable masticatory process and the mandibles are but feebly developed. The earliest conchostracan. 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 perfect
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
