Century Dictionary and Cyclopedia
- n. The embryonal or primitive shell of an ammonoid cephalopod. Owen. Also called embryo-sac, oviccll, and ovisac.
- n. The apical whorl of a gastropod shell.
GNU Webster's 1913
- n. (Zoöl.) The embryonic shell, or first chamber, of ammonites and other cephalopods.
- proto- + conch (Wiktionary)
“I'd be very interested in reading any studies that have examined the strength of genetic separation in examples like this same family, similar shell form, radically different protoconch.”
“The fine spiral lines of the protoconch are more likely to represent the still developing mantle anatomy of the snail embryo at the time of the secretion of its embryonic shell.”
“There are very many such examples in the Australian Charopidae and the normal practice which I agree with is to regard such strong protoconch differences as automatically significant at generic level in view of the unlikelihood that there is much evolutionary pressure affecting protoconch fsculpture.”
“However, one significant trait distinguishes B. gymnesica from both Mastus and Napaeus: the protoconch, or the embryonic whorls, of Balearena have spiral lines on bottom halves of whorls, whereas the Mastus and Napaeus protoconches are always devoid of such microsculpture.”
“Balearena gymnesica, enture shell 1 and protoconch.”
“Growth: Even before the snail hatches, it has formed a single small whorl around itself known as a protoconch.”
“Even before the snail hatches, it has formed a single small whorl around itself known as a protoconch.”
“As Altaba also notes, the protoconch microsculpture probably doesn’t have anything to do with burrowing, or for that matter, have any function at all.”
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Words that have only one of the vowels. On this list I include only words with at least three vowels. When I first started the list, if a word had several forms, I generally listed only the one wit...
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