174 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



above — and which it must be remembered are not yet 

 finished — give results of a re-assuring nature, and demand 

 from the public at the very least a suspension of 

 judgment, while they also indicate the advantage of 

 adopting some simple sanitary measures which, if properly 

 carried into effect, would go far to remove suspicion from 

 the oyster in our markets. These measures are, 1° a 

 strict examination of all grounds upon which oysters are 

 grown or bedded so as to ensure their freedom from 

 sewage, and 2°, if practicable, the use of " degorgeoirs " 

 or disgorging tanks in which the oysters should be placed 

 for a short time before they are sent to the consumer. 



Explanation of the Plates. 



Plate I. 



Stenhelia herdmani, n. sp. (A. Scott). 



Fig. 1. Female seen from the side, X 27. 2. Antennule, 

 X 63. 3. Antenna, X 85. 4. Mandible, X 85. 

 5. Maxilla, X 85. 6. Anterior foot-jaw, X 127. 

 7. Posterior foot-jaw, X 90. 8. Foot of first 

 pair of swimming feet, X 85. 9. Foot of fourth 

 pair, X 85. 10. Foot of fifth pair, X 127. 11. 

 Abdomen and caudal stylets, X 170. 

 Stenhelia similis, n. sp. 



Fig. 12. Female seen from the side, X 40. 13. Anten- 

 nule, X 127. 14. Antennule of male, X 127. 

 15. Antenna, X 125. 16. Mandible, X 253. 

 17. Maxilla, X 253. 18. Posterior foot-jaw, X 

 253. 19. Eostrum, X 253. 20. Foot of first 

 pair of swimming feet, X 127. 2L Foot of 



