Stereomicroscopy observation of the leech in different environments

The leeches were divided into four groups (n=10). Leeches in the untreated group were placed directly into deionized water. Leeches in the frozen group were frozen at −80°C for 2 h and then placed in deionized water. Leeches in the desiccation group were dehydrated at 85% humidity for 48 h. Leeches in the ethanol-treated group leeches were immersed in ethanol for gradient dehydration (50%, 70%, 80%, 90%, ascending ethanol, 15 min per step, followed by 100% ethanol for 30 min). Body shapes were immediately observed under a stereomicroscope after processing.