. Outlines of zoology. Zoology. ENTOMOSTRA CA. 265 and is protected by a shield-like or bivalve shell. The mandibles are without palps, and the maxillae are rudimentary. (a) Branchiopoda. The body has numerous segments and (10-20 or more) appendages with respiratory plates. The shell is rarely absent, usually shield-like or bivalved. The heart is a long dorsal vessel with numerous openings. The eggs are able to survive prolonged desiccation in the mud. Branchipus, a beautifully coloured fresh-water form, with hardly any shell. Artemia. Brine-shrimps. Periodically parthenogenetic. By gradually
. Outlines of zoology. Zoology. ENTOMOSTRA CA. 265 and is protected by a shield-like or bivalve shell. The mandibles are without palps, and the maxillae are rudimentary. (a) Branchiopoda. The body has numerous segments and (10-20 or more) appendages with respiratory plates. The shell is rarely absent, usually shield-like or bivalved. The heart is a long dorsal vessel with numerous openings. The eggs are able to survive prolonged desiccation in the mud. Branchipus, a beautifully coloured fresh-water form, with hardly any shell. Artemia. Brine-shrimps. Periodically parthenogenetic. By gradually changing the salinity of the water, Schmankewitsch was able, in the course of several generations, to modify A. salina into A. milhattsenii, and vice versd. Artemia fertilis is one of the four animals known to occur in the dense waters of Salt Lake. Apus, a fresh-water form with a large dorsal- shield. Periodically parthenogenetic. One species heimaphrodite. Of these, Apus is certainly the most interesting. It is over an inch in length, and therefore a giant among Entomostraca. It has an almost world-wide distribu- tion. " It possesses peculi- arities of organisation which mark it out as an archaic foim, probably standing nearer to the extinct an- cestors of the Crustacea than almost any other living member of the ; The appendages are very numerous and mostly leaf-like. They may be regarded as representing a primitive type of Crustacean limb. Professor Ray Lankester enumerates them as follows :—. Fig. surface of Apus cancriformis. — From Bronn's " ; In the anterior region are the two com- pound eyes, and behind them the simple unpaired eye. The whip-like outgrowths of the first thoracic ap- pendage project laterally. Pre-oral. Oral. 1. Antenna. 2. Second antenna. (This is sometimes absent, and apparently always in certain species.) 3. Mandible. 4. Maxilla. 5. Please note that these images are extracted from sca
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
