. Cephalopoda. Cephalopoda. FIGURE 142. Young Abraliopsis morrisi from Messina (July 1911). 5x. The following characters are more distinct than in the preceding stage: modification of the fins (which are slightly wider in life); enlargement and displacement of the eyes; the growth of the ventral arms; modification of the clubs; formation of hooks and protective margins on the arms and the relative shortening of the arms. The olfactory papillae are situated lateral to the funnel; the low, wide elevations medially and anterior to the papillae belong to the boundary of the funnel pit, the lateral
. Cephalopoda. Cephalopoda. FIGURE 142. Young Abraliopsis morrisi from Messina (July 1911). 5x. The following characters are more distinct than in the preceding stage: modification of the fins (which are slightly wider in life); enlargement and displacement of the eyes; the growth of the ventral arms; modification of the clubs; formation of hooks and protective margins on the arms and the relative shortening of the arms. The olfactory papillae are situated lateral to the funnel; the low, wide elevations medially and anterior to the papillae belong to the boundary of the funnel pit, the lateral end corresponds to the ventral (fourth) longitudinal fold of the neck (see Figure 137). The eyes are very large and displaced laterally, resembling the definitive form of the head. Arms and tentacles are relatively shorter than in the preceding stage, perhaps due to preser- vation. The tentacles are particularly thick; they taper toward the clubs, which are whiplike at the end (Figure 127). The length of the arms is different at this stage. The third pair is now as long as the second; the fourth is only slightly shorter than the second and much longer than the first. The suckers of the arms are converted into hooks which still resemble the form of suckers except on the basal and distal part (hooklike suckers). The protective margins show the characters described above (p. 293). They are wide on the ventral sides of the second and third pairs of arms, but weak or rudimentary elsewhere. There are hardly any indications of protective margins on the clubs. The basal suckers of the club are still distinctly biserial. The carpal group consists of 4 large suckers on each side. There are 6 suckers on the left side and 5 small ones on the right side before the hand part, some of which fall off later. There is a ventral median row of 3 larger hooks on each side of the hand part; the adjacent marginal row has already been lost. The dorsal median and 295 marginal rows still contain small
Size: 1088px × 2296px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectcephalopoda
