ACTINIANS FROM THE BAHAMA ISLANDS 113 



ten in conjunction with Miss Shackleton ('91), has shown that there 

 is little probability that the species assigned to the genus Mammillifera 

 by Erdmann present the characters of the forms upon which that genus 

 was founded by Lesueur ('17), and employs the generic term used by 

 Gray ('28) for a tuberculate Zoanthid. I agree with Haddon's con- 

 clusions as to this matter, and have therefore followed his example in 

 using the name Isaurus. 



The form described by Gray was from an unknown locality and was 

 given the specific name tuber culatus. I found among the Bermudan 

 forms which I studied a species which seemed to agree closely with 

 Gray's descriptions, and I identified it with his species. At the same 

 time I also identified the species described by Duchassaing and 

 Michelotti with this same form, an identification I now find to have 

 been erroneous. The tuberculate Zoanthid in the Northrop collection 

 is undoubtedly identical with the form described by Duchassaing and 

 Michelotti, but it presents unmistakable differences from the Bermuda 

 species, and must be regarded as distinct from it. The specific name 

 given by Duchassaing and Michelotti being preoccupied by Gray's 

 species, a new name must be bestowed, and the term proposed by 

 Andres ('83) seems most appropriate. Duchassaing and Michelotti's 

 species may therefore be known as Isaurus duchassaingi. 



The appearance of the living animal in its contracted condition is 

 shown in fig. 6, and I take the following description of it from Dr. 

 Northrop's notes. The animals are found growing in groups of five or 

 six, for the most part disconnected, though one specimen had con- 

 nected with it a smaller individual, evidently produced by budding, 

 and it may be presumed that each group owes its existence to this 

 process, the various individuals separating from one another after a 

 time. Duchassaing and Michelotti figure two individuals united by a 

 stolon-like ccenenchyme, but in the preserved individuals I examined 

 separation had taken place. In color the polyps were yellowish, closely 

 resembling their surroundings, the disk and tentacles being of the same 

 color as the column. The base is firmly adherent, and the column is 

 "nearly cylindrical, but generally contracted near the base and often 

 at intervals above, giving the animal a rather grotesque appearance. 

 When slightly contracted the column bears a number of tubercles, 

 which, though irregularly distributed, are more numerous near the 

 top. In preserved and contracted specimens these tubercles are 



