MOLGULA MANHATTENSIS DeKay 



Material. Molgula manhattensis is quite common along 

 the Atlantic Coast and may be preserved by simply putting the 

 specimens into weak formalin. Every student should receive 

 two specimens. 



Descriptive Part 



Molgula manhattensis is a common representative of the 

 Order Monascida, Class Urochorda (or Tunicata), Phylum 

 Prochordata. How much the Tunicates have in common with 

 the Cephalochorda and Hemichorda (Enteropneusta), the other 

 two classes referred to the same phylum by modern zoologists, 

 is a matter for future investigators to decide. I for one do not 

 think that there is much in common between these three classes. 

 Meanwhile Molgula may be studied as a typical representative 

 of the Tunicates. 



Molgula has almost the shape of an egg. At the anterior end 

 it is produced into a short tube the incurrent or buccal siphon, 

 not far from which is another short tube the excurrent or cloacal 

 siphon. The edge of the former has six lobes, that of the latter 

 four lobes. The semitranslucent external wall of the animal is the 

 tunique. It has the consistency of hard gelatine, is nothing but 

 a very thick cuticle secreted by the hypodermis of the body 

 wall, and is always covered with grains of sand. These sand 

 grains are firmly attached to the tunique owing to the adhesive 

 quality of the radicoid filaments which cover the entire surface 

 of the tunique. 



The tunic contains amoeboid mesodermic cells, but these 

 cells do not belong to it. They are immigrants from the mesen- 

 chyme. Numerous branched vascular diverticle^ are found in 



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