REPORT ON THE ECHINOIDEA 



Collected by the Barbados-Antigua Expedition 

 from the University of Iowa in 1918 



Hubert Lyman Clark 



Museum of Comparative Zoology, Cambridge 



The collection of Echinoidea made by the party from the 

 University of Iowa, which under the leadership of Professor 

 C. C. Nutting, visited Barbados and Antigua in the summer of 

 1918, is not a large one but it represents well the typical littoral 

 West Indian fauna. The 229 specimens belong to 18 species, all 

 but two of which are known, characteristic forms of the Carib- 

 bean region. The two exceptions are notable indeed, for each 

 represents a genus not hitherto reported from the West Indies: 

 one (Pseudoholetia) is recorded from the eastern Atlantic (As- 

 cension Island) and the other {Centrostephanus) occurs on the 

 western coast of Mexico. 



Of the 229 specimens, 178 belong to three very common West 

 Indian species, Echinometra lucnnter, Echinoneus cyclostomus 

 and Brissus hrissiis. The equally common species, Centrecliinus 

 antillarum, Tripneustes esculentus and Lytechinus variegatus, 

 are represented by very few specimens, presumably because their 

 large size made extensive series undesirable and their common- 

 ness made such series unnecessary. These six common species 

 occurred at both Barbados and Antigua. The only other echini 

 found at the latter island were Eucidaris trihidoides and Cly- 

 peaster rosaceus, which are also common and widespread species. 

 But no Clypeaster was taken at Barbados. 



The 18 species fall naturally into two divisions, those which 

 occur along shore, or on reefs easily accessible at low tide, and 

 those which are gotten only by dredging, trawling or the use of 

 tangles. The former are the strictly "littoral" group; the latter 

 belong rather to the ' ' continental ' ' fauna ; of course members of 

 the littoral group are often taken in deeper water, sometimes 



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