25 Trivia arctica
COMPARISON of egg capsules of Lamellaria perspicua (A), T. monacha (B) and T. arctica (C & D) embedded in compound ascidian.
'A&B' based on drawings and descriptions in Lebour (1931 & 1933) and Fretter & Graham (1962), and photographs by P. Lightfoot.
Capsules of T. arctica are virtually identical with those of T. monacha.
Further information and images of egg capsule of T. arctica, at 21Ta flic.kr/p/D3iJt7 and 21.1Ta flic.kr/p/234LSrM .
Images C & D are close ups from image 21.1Ta flic.kr/p/234LSrM . The neck of the egg capsule is colourless transparent and almost invisible, so the outline has been indicated with dots. In 'C' the ventral pedal gland is inside the part-formed neck shaping the plug that seals the egg chamber until hatching. In 'D' the flexible tip of the ventral pedal gland is forming the flared lip of the funnel-shaped neck.
1: compound ascidian.
2: surface of compound ascidian raised around rim of lid of L. perspicua capsule.
3: buff ova seen through transparent side of recently deposited L. perspicua egg-capsule; eggs become white and capsule expands with age.
4: long neck of T. monacha capsule projects well above surface of ascidian.
5: plug at base of funnel mouth of T. monacha capsule.
6: orange ova (colour reported by Lebour, 1931) seen through transparent side of recently deposited T. monacha egg-capsule. Lebour reported that bright-yellow or orange forms of Diplosoma were preferred and rearing succeeded on it. Orange Botryllus and Trididemnum were also used for egg-laying in captivity, but rearing failed.
Photographs; Zierikzee, Netherlands, March 2017 © S. Verheyen.
Full SPECIES DESCRIPTION: flic.kr/p/Cfnfpb
Albums of OTHER SPECIES:
25 Trivia arctica
COMPARISON of egg capsules of Lamellaria perspicua (A), T. monacha (B) and T. arctica (C & D) embedded in compound ascidian.
'A&B' based on drawings and descriptions in Lebour (1931 & 1933) and Fretter & Graham (1962), and photographs by P. Lightfoot.
Capsules of T. arctica are virtually identical with those of T. monacha.
Further information and images of egg capsule of T. arctica, at 21Ta flic.kr/p/D3iJt7 and 21.1Ta flic.kr/p/234LSrM .
Images C & D are close ups from image 21.1Ta flic.kr/p/234LSrM . The neck of the egg capsule is colourless transparent and almost invisible, so the outline has been indicated with dots. In 'C' the ventral pedal gland is inside the part-formed neck shaping the plug that seals the egg chamber until hatching. In 'D' the flexible tip of the ventral pedal gland is forming the flared lip of the funnel-shaped neck.
1: compound ascidian.
2: surface of compound ascidian raised around rim of lid of L. perspicua capsule.
3: buff ova seen through transparent side of recently deposited L. perspicua egg-capsule; eggs become white and capsule expands with age.
4: long neck of T. monacha capsule projects well above surface of ascidian.
5: plug at base of funnel mouth of T. monacha capsule.
6: orange ova (colour reported by Lebour, 1931) seen through transparent side of recently deposited T. monacha egg-capsule. Lebour reported that bright-yellow or orange forms of Diplosoma were preferred and rearing succeeded on it. Orange Botryllus and Trididemnum were also used for egg-laying in captivity, but rearing failed.
Photographs; Zierikzee, Netherlands, March 2017 © S. Verheyen.
Full SPECIES DESCRIPTION: flic.kr/p/Cfnfpb
Albums of OTHER SPECIES: