a. and sb. Zool. [f. A- pref. 14 + SIPHONATE.] A. adj. Having no respiratory siphon. B. sb. An acephalous mollusk so characterized.
1859. Owen, Classif. Mamm., 61. Holostomatous and asiphonate Gastropods.
1879. Le Conte, Elem. Geol., 304. Lamellibranchs are divided into Siphonates and Asiphonates.
