| Word: Actinocyte Description: Elongated contractile cell often grouped in sphincter- like structure around the osculum, below the sieve- plates, and around the large exhalant canals. Characterized by numerous filaments of actin within their cytoplasm. New term for the contractile cell (ac in figure). Synonyms: Myocyte Category: Cytology |
| Word: Apopinacocyte Description: Endopinacocyte lining the exhalant canal (ai in figure). Category: Cytology |
No image available. | Word: Apopinacoderm Description: Surface lined by apopinacocytes. Category: Cytology |
| Word: Apopylar cell Description: Cell surrounding the apopyle and located between the choanocytes and the apopinacocytes (ay in figure). Category: Cytology |
| Word: Archaeocyte Description: Amoeboid cell with large nucleolus and capable of phagocytosis. May differentiate into other types of cells (ar in figure). Category: Cytology |
| Word: Bacteriocyte Description: Cell containing prokaryotic microsymbionts Category: Cytology |
| Word: Basopinacocyte Description: Pinacocyte affixing the sponge to the substratum by external secretion of a collagenous matrix (bs in figure). Category: Cytology |
| Word: Central cell Description: Single cell located at the apopyle of choanocyte chambers Category: Cytology |
| Word: Choanoblast Description: Cell that buds anucleate outgrowth called COLLAR BODY; in Hexactinellida Category: Cytology |
| Word: Choanocyte Description: Cell having a flagellum that is surrounded by a collar of cytoplasmic microvilli linked by bridges of glycocalyx. Several are typically arranged in spherical, ovoid, or elongated chambers. Fundamental cell of sponges (ch in figure). Category: Cytology |
No image available. | Word: Choanoderm Description: Surface lined by choanocytes. Category: Cytology |
| Word: Collar body Description: Anucleate choanocyte in hexactinellids. Category: Cytology |
| Word: Collencyte Description: Cell with branching pseudopods, involved in the secretion of collagen (co in figure). Category: Cytology |
| Word: Cystencyte Description: Cell with a single large vesicle containing amorphous material identified as polysaccharide and occupying most of the cell volume Category: Cytology |
| Word: Endopinacocyte Description: Pinacocyte lining the inhalant and exhalant canals. In some Demospongiae orders, it has a flagellum (en in figure). Category: Cytology |
No image available. | Word: Endopinacoderm Description: Surface lined by endopinacocytes. Category: Cytology |
No image available. | Word: Eosinophilic cell Description: Cell with inclusions that react positively with eosine. Category: Cytology |
| Word: Exopinacocyte Description: Fusiform or T-shaped pinacocyte covering the free surface of a sponge. In exceptional cases, it has a flagellum (Homoscleromorpha) (ex in figure). Category: Cytology |
No image available. | Word: Fuchsinophilic cell Description: Cell with inclusions that react positively with acid fuchsin. Category: Cytology |
| Word: Globoferous cell Description: Cell with a single large globule, a reduced cytoplasm, and a small conical nucleus (Clathriidae) Category: Cytology |
| Word: Glycocyte Description: Cell with conspicuous dictyosomes, characterized by the presence of glycogen rosettes and osmiophilic inclusions. Also known as gray cell Synonyms: Gray cell Category: Cytology |
| Word: Lophocyte Description: Collencyte with a characteristic tuft of collagen fibrils attached to the posterior pole (lo in figure). Category: Cytology |
| Word: Mesohyl Description: Part of sponge enclosed by pinacoderm and choanoderm (= "mesenchyme," term to be rejected for sponges). Category: Cytology |
No image available. | Word: Mesolamella Description: Sheet of collagen separating the choanochambers of hexactinellids. Category: Cytology |
| Word: Microgranular cell Description: A cell with cytoplasm filled with small dense granules Category: Cytology |
| Word: Microsymbiont Description: Prokaryotic or more rarely eukaryotic microorganism living inside a sponge. May be unicellular or multicellular filamentous, with or without pigments, and may occur intra- or intercellularly Category: Cytology |
| Word: Pinacocyte Description: Cell delimiting the sponge from the external milieu and always only in a layer one-cell deep Category: Cytology |
| Word: Pinacoderm Description: Surface lined by pinacocytes (ex and en in figure). Category: Cytology |
| Word: Pocket cell Description: Special kind of bacteriocyte that surrounds an area of the intercellular matrix, including microsymbionts Category: Cytology |
| Word: Porocyte Description: Cell surrounding a pore (ostium) Category: Cytology |
No image available. | Word: Prosopinacocyte Description: Endopinacocyte lining the inhalant canals. Category: Cytology |
No image available. | Word: Prosopinacoderm Description: Surface lined by prosopinacocytes. Category: Cytology |
| Word: Rhabdiferous cell Description: Large cell with numerous rod-like inclu sions parallel to the long axis of the cell containing acid mucopolysaccharides Category: Cytology |
| Word: Sclerocyte Description: Cell involved in spicule secretion. In Demospon- ges, with intracellular secretion, sclerocytes are characterized by numerous mitochondria and the presence of spicule-axial filaments. In Calcarea, where secretion is extracellular, sclerocytes have septate junctions between them (sc in figure). Category: Cytology |
| Word: Spherulous cell Description: Cell filled with large round spherules that occupy almost the entire cell body, compressing the cytoplasm into thin sheets (sp in figure). Category: Cytology |
| Word: Spongocyte Description: Cell secreting spongin fibers (so (spo = spongin) in figure). Category: Cytology |
| Word: Thesocyte Description: Vitelline-rich archaeocyte in a sponge gemmule (th in figure). Category: Cytology |
No image available. | Word: Trabecular tissue Description: Syncytia in hexactinellids occurring around the choanochambers. Category: Cytology |
| Word: Trophocyte Description: Nurse cell involved in the initial stages of gemmule and oocyte formation. Category: Cytology |