INVERTEBRATA OF MASSACHUSETTS. 



Class TUNICATA.* 



Acephalous Mollusks with a soft, orgixiiizod, coriaceous or gelat- 

 inous shell or test provided with a branchial and an anal orifice. 

 Mantle forming an interior coat. Gills attached wholly or partly 

 to the internal surface of the mantle. Mouth without labial tenta- 

 cles, placed below the gills. Animals single or aggregate, fixed or 

 free, hermaphrodite, undergoing a metamorphosis in their young- 

 state. 



The Tunicaries are entirely marine, and are very numerous in all 

 parts of the world ; adhering to rocks and sea-weed, their strange, 

 bag-shaped, leatliery bodies may be seen along the strand at low- 

 water, ejecting, when touched, the sea-water to some distance ; and 

 on the ocean their lengthened sinuous chains, or pellucid phospho- 

 rescent tubes, cannot fail to arrest the eye of the voyager. The com- 

 pound forms exhibit, in the varied arrangement of the individuals 



* Finding nothing in Dr. Gould's manuscript relating to the Ascidians, and being my- 

 self unacquainted with the class, I could but collate the few pul)lished descriptions of spe- 

 cies, and obtain what drawings had been made by those who have collected the animals. 

 Through the kindness of Professor Agassiz, the rich treasures of the Museum of Compara- 

 tive Zoology have been laid open to me, furnishing many figures beautifully drawn front 

 nature by Mr. Burkhardt. Dr. Packard has also given the use of the species collected by 

 him, from which Mr. Morse has drawn Plate XXIII. as correctly as is possible from speci- 

 mens long preserved in alcohol. 



To Mr. Alexander Agassiz I am indebted also for the use of the woodcuts of Salpa. 



The descriptions of families, genera, &c., are copied from " The Genera of Recent Mol- 

 lusca." I have included all species actually described as having been found from New 

 York to Labrador. A reference to the " Bibliography of North American Conchology " 

 will show that species have been mentioned by name as inhabiting New England which 

 are not included in the following pages. They are not accompanied by descriptions. 



W. G. B. 

 1 



