In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: CONCLUSIONS : High concordance in major developmental anomalies between Wistar and SD rats were noted with the exception of VSD in the SD rats and hydrocephalus in the Wistar rats .
### Output Text:
CONCLUSIONS : High concordance in major developmental anomalies between Wistar and SD rats were noted with the exception of VSD in the SD rats and hydrocephalus in the Wistar rats . 