Structure and function of the posterior vas deferens of the snow crab, <i>Chionoecetes opilio</i> (Brachyura, Majidae)
Bibliographic record
Abstract
Summary The structure and function of the posterior vas deferens (PVD) of the male snow crab, Chionoecetes opilio, were studied by light and electron (SEM/TEM) microscopy. The vas deferens is divided into three regions: anterior (AVD), median (MVD) and posterior (PVD). Spermatophores are formed in the AVD and moved to the MVD where they are stored within droplets of seminal fluid. Seminal fluid and spermatophores are strongly PAS positive. The reaction with alcian blue-PAS indicated the presence of neutral polysaccharides. The PVD is further divided into the distal and proximal regions that differ in structure and function. In the distal region of the PVD, the epithelial cells are columnar containing lobed nuclei. The lumen contains a mixture of lysed spermatozoa and spermatophores. Numerous heterophagic vacuoles present at the cell surface are absorbed and digested intracellularly. The cytoplasm contains a large amount of rough endoplasmic reticulum and lysosomes associated with Golgi complexes and few mitochondria. TEM observations reveal that the primary function of this region is the phagocytosis of excess spermatozoa. The digestive function of the distal region of the PVD suggests that this mode of secretion is apocrine. The proximal region of the PVD contains neither spermatophores nor free spermatozoa. The epithelium is composed of cuboidal cells with elongate nuclei. The apical microvilli are short and regularly arranged. The lumen contains a large quantity of an amorphous, jelly-like substance, which is the secretory product of the distal region of the PVD. In the cytoplasm rough endoplasmic reticulum and Golgi complexes are absent. We conclude that the proximal region of the PVD, therefore, is used for storage of highly acidic seminal fluid. The function of the PVD for the destruction and resorption of spermatophores and spermatozoa has not previously been reported in other decapods.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".