title: Ultrastructure of cardiac muscle of Trochosa terricola Thor., Pardosa amentata Clerck, P. pullata Clerck, and Pisaura mirabilis Clerck (Araneae: Lycosidae, Pisauridae).
abstract: The ultrastructure of the cardiac muscle in some araneae has been investigated. The sarcolemma invaginates at the Z band and may extend into the cells through several myofibrils. Numerous T-tubules are given off both from sarcolemmal invaginations and also directly from the cell surface. In passing through the Z band, the luminal diameter of T-tubules greatly increases. Dyadic and a few triadic couplings are found mainly at the A-I level. Peripheral couplings were not seen.
mesh_terms: D000818:Animals; D008854:Microscopy, Electron; D008931:Mitochondria, Muscle; D009206:Myocardium / Q000648:ultrastructure*; D009210:Myofibrils; D012508:Sarcolemma; D012519:Sarcoplasmic Reticulum; D013112:Spiders / Q000033:anatomy & histology*