134 Invertebrate Zoology. 



A SIMPLE TUNICATE, 



(Molgula manhattensis*) . 



THIS species is quite abundant along the New England 

 shores, attached to submerged stones and woodwork. 

 Though occasionally solitary, the individuals are more often 

 found in clusters of varying sizes. It is our most common 

 Simple Tunicate, and is related to the dona so frequently 

 mentioned in the European text-books. 



External Anatomy. Though individual specimens 

 vary, the more general shape of the present species is that 

 of a two-necked flask, the larger neck or siphon serving for 

 the entrance of water and food, the other, slightly smaller 

 and often abruptly curved, serving for the escape of the 

 strained water, the waste products of digestion and excre- 

 tion, and also for the egress of the ova or embryos. The 

 incurrent opening or mouth is surrounded by a series of 

 circum-oral lobes or tentacles, which may be folded in such 

 a way as to completely close the orifice. Are similar lobes 

 arranged around the excurrent or cloacal opening? The 

 outer surface of the animal has a felty appearance, due to 

 the presence of innumerable papilla. The papillae entangle 

 foreign matter, and thus the animal secures a protective 

 coloring. In certain specimens the deeply colored vis- 

 cera are to be seen through the semi-transparent body 

 walls. 



