( I \ E KTN EUS SPOO N - W O K M . 250 



SIPUNCULIDJE. THALASSEMA CEJE. 



Genus Thalassemia. Cuvier. 



Generic Character, — Body cylindrical, posterior extremity smooth; proboscis 

 retractile, short, without tentacula, and furnished at one side with a long fleshy 

 furrowed simple sheath or appendage, which is not retractile. 



GAERTNEITS SPOON- WORM. 



Thalassemia Neptuni. Gaertner. 



Specific Character. — Body purplish anteriorly, gray posteriorly ; appendage 

 saffron. 



Lumbricus Thalassemia, Pallas, Spicel. Zool. fasc. x. p. 8, t. i. f. 6. Gmelin, 



Syst. p. 3084. 

 Thalassema rupium, Lamarck, Syst. (1801) p. 329. 

 Thalassina mutatoria, Montagu, Lin. Trans, vol. XI. p. 24, t. v. f. 2. 



Among the many contributions sent from England by 

 Gaertner to Pallas was the singular worm-like Echinoderm 

 before us. Its sagacious discoverer evidently saw the neces- 

 sity of constituting a genus for its reception ; and though 



he does not appear to have defined it, he gave the name 



s2 



