(A) anterior end demonstrating the bulbiform esophagus (BE); (B) buccal capsule (BC); (C) posterior end with the anus (AN) and dorsoventrally
The propodials are thick and wide, dorsoventrally
For example, Catalina Island shells were more dorsoventrally
compressed (positive CV1 value), whereas Dungeness West clams were more dorsoventrally
expanded (negative CV1 value) in comparison with shells from all other locations.
acheilognathi have a segmented body with an arrow-head-shaped or heart-shaped scolex with bothria (slits) situated dorsoventrally
along the scolex terminating with a weak apical disc 143.
The mandibular space is narrow, the ventral margin is slightly convex and the lateral face is oblique dorsoventrally
. The alveolar margin has six alveoli for the lower molar teeth, which increase in size rostrocaudally.
The larval stage of Ischyomius is known (author's collection and material borrowed from Jim McClarin) but is yet undescribed; it exhibits the following general features: body elongate, parallel-sided, only slightly flattened dorsoventrally
; head with 5 stemmata (3 anterior and 2 posterior); urogomphal plate with dorsal tubercles and multiple inner teeth on urogomphi; sternite 9 with transverse row of asperities.
1A) broad, dorsoventrally
flattened, arched along longitudinal axis, strongly chitinized, and tapering posteriorly.
nivalis, such as habitat (from areas above the tree line usually at altitudes well above 2000 m a.s.), growth habit (rosulate herbs < 10 cm in height, with well-developed rhizomes), leaf morphology (leaves < 10 cm long, with pinnatifid to pinnate blades) and floral morphology (flowers axillary, erect and solitary; sepals reduced and inconspicuous; corollas white, half to full spreading; nectar scales contrastingly coloured yellow to orange, with three dorsoventrally
flattened dorsal threads, attached to the distal-most third of the scale's back).
The endophallic valves are long and slender, wide and dorsoventrally
flattened basally, but laterally compressed and narrow apically.
The visceral side of the bone is featureless and ornamented only by dorsoventrally
directed striations formed during bone growth.
The right eyes were cut vertically (dorsoventrally
) and the left eyes cut horizontally (temporonasally).
While retaining certain plesiomorphic characteristic, such as a dorsoventrally
extensive, medially deep and posteriorly pocketed POF and deeply incised ectoflexid on the mandibular premolar teeth.