metatrochophore
Image:Pomatoceros lamarckii metatrochophore.jpg image of metatrochophore of annelid Pomatoceros lamarckii (family Serpulidae){{cite journal |last1=McDougall |first1=Carmel |last2=Chen |first2=Wei-Chung |last3=Shimeld |first3=Sebastian M. |last4=Ferrier |first4=David E. K. |journal=Frontiers in Zoology |date=2006 |volume=3 |issue=1 |pages=16 |doi=10.1186/1742-9994-3-16|pmid=17032451 |pmc=1615870 |title=The development of the larval nervous system, musculature and ciliary bands of Pomatoceros lamarckii (Annelida): heterochrony in polychaetes |doi-access=free }}
ey = eyspot]]
A metatrochophore ({{IPAc-en|ˌ|m|iː|t|ə|ˈ|t|r|oʊ|k|ə|ˌ|f|ɔər|,_|ˌ|m|ɛ|-|,_|-|ˈ|t|r|ɒ|-|,_|-|k|oʊ|-}};{{refn|{{Cite dictionary |url=http://www.lexico.com/definition/Meta |archive-url=https://web.archive.org/web/20201111210908/https://www.lexico.com/definition/meta |url-status=dead |archive-date=2020-11-11 |title=Meta |dictionary=Lexico UK English Dictionary |publisher=Oxford University Press}} {{Cite dictionary |url=http://www.lexico.com/definition/Trochophore |archive-url=https://web.archive.org/web/20200322185819/https://www.lexico.com/definition/trochophore |url-status=dead |archive-date=2020-03-22 |title=Trochophore |dictionary=Lexico UK English Dictionary |publisher=Oxford University Press}}}}{{refn|{{Dictionary.com|accessdate=2016-01-24|Meta}} {{Dictionary.com|accessdate=2016-01-24|Trochophore}}}}) is a type of larva developed from the trochophore larva of a polychaete annelid.
The metatrochophore of a deep-sea hydrothermal vent vestimentiferan has a foregut and a midgut. The foregut cells have several microvilli, basal bodies, and cilia, with e-dense granules dispersed in the apical cell region. The diameter of the midgut in one specimen was 50 μm and the lumen’s diameter was 7 μm, in which the cilia extended and e-dense material was found. The midgut cells had fewer cilia than the fore- and hindgut cells but exhibited an extensive, e-dense brush of microvilli and a nucleus in the apical third of the cell body. Additionally, the midgut contained a few bacteria in the lumen. {{cite web |last1=Bright |first1=Monika |title=The metatrochophore of a deep-sea hydrothermal vent vestimentiferan (Polychaeta: Siboglinidae) |url=https://link.springer.com/content/pdf/10.1007/s13127-012-0117-z.pdf |website=link.springer.com |publisher=Organisms, Diversity and Evolution |access-date=15 March 2024}}
Metatrochophores have a number of features trochophores lack, including eyespots and segments.