356 OX A COLLECTION OF ECHIUHIDS, ETC. 



EXPLANATION OF PLATE XXXIII. 



Fig. 1. An anterior and slightly ventral view of Thalassema baronii. Natural size. 



Fig. 2. A view of Thalassema diaphanes. x 1-5. 



Fig. 3. A ventral view of Thalassema kokotoniense. Natural size. 



Fig. 4. A sketch of TJialassema erythrogrammon taken from a drawing made by Dr Willey 

 from the living specimen. The papillae, which are much more apparent when the animal is 

 in a state of contraction, are only shown over a small band, but they are not confined to this 

 band. 



Fig. 5. A view of Thalassema neptuni, killed in an expanded condition. 



Fig. 6. A view of ThaUcssema neptuni, killed in a contracted condition. The specimens 

 in figures 5 and 6 weigh almost exactly the same, they are drawn so as to show the differences 

 of size and outline produced by the method of killing. 



Fig. 7. A portion of the skin of a Thalassema baronii taken from the ventral surface, 

 showing the nervous system, the coiled internal openings of the four nephridia a, the longi- 

 tudinal muscles b, and the intervals between adjacent muscles c. 



