Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by CRAGG, S. M.
Right arrow Search for Related Content
PubMed
Right arrow Articles by CRAGG, S. M.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

J. Moll. Stud. (1989), 55, 497-508
© The Malacological Society of London 1989

research-article

THE CILIATED RIM OF THE VELUM OF LARVAE OF PECTEN MAXIMUS (BIVALVIA: PECTINIDAE)

S. M. CRAGG*

N.E.R.C. Unit of Marine Invertebrate Biology, Marine Science Laboratories Menai Bridge, Gwynedd LL59 5EH, U.K.

During the early development of Pecten maximus, the prototroch of the trochophore becomes the rim of the velum of the veliger. The prototroch consists of a tract of randomly-distributed cilia, but in the veliger an ordered pattern of ciliation with some compound cilia develops. The thin epithelium connecting the velum to the body of the larva bears no cilia, nor does the upper surface of the velum (except for an apical tuft); the much thicker epithelium of the velum rim, however, is profusely ciliated. The cilia are arranged in five bands or rings each extending round the rim of the velum. The ring closest to the upper (i.e. ventral) surface of the velum is the inner preoral ring of single cilia. Below this are two rings of much longer cilia grouped to form blade-shaped cirri, which each consist of 2 or 3 rows of 10-15 cilia. The cilia substructures indicate that the direction of active beat of the cirrus is along the axis of the rows. This beating generates the main swimming current. The energy demands of beating are reflected in the numerous large mitochondria in the cells bearing the cirri. Nerve processes in the velum may control beating. Below the cirri are an adoral tract of shorter cilia and then a ring of postoral cilia. The velum anatomy is that of a typical bivalve veliger, but some features distinguish Pecten maximus from other bivalves. The onfiguration of the bands of cilia and the orientation of their beating suggest that the veliger captures food particles by the ‘opposed band’ method. This configuration is likely to be homologous with those of other spiralian larvae.

*Present address: School of Biological Scrences, Portsmouth Polytechnic, King Henry I Street, Portsmouth, PO1 2DY, U.K.

(Received 30 September 1988; accepted 1 December 1988)


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J MOLLUS STUDHome page
K. Lundin, C. Schander, and C. Todt
Ultrastructure of epidermal cilia and ciliary rootlets in Scaphopoda
J. Mollus. Stud., February 1, 2009; 75(1): 69 - 73.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.