Collected by the late Dr. J. I. Northrop. 191 



('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 ('It), and employs the generic term used hy Gray ('28) 

 for a tuberculate Zoanthid. I agree with Haddon's conclusions 

 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 tuherculatus. 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 aud Michelotti with this same form, an identifica- 

 tion I now find to have been erroneous. The tuberculate Zoan- 

 thid 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 Duchas- 

 saing 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 Duchassairrgi. 



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 speci- 

 men had connected with it a smaller individual, evidently pro- 

 duced 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 coenenchyme, but in 

 the preserved individuals I examined, separation had taken place. 

 In color the polyps were yellowish, closely resembling their sur- 

 roundings, the disc 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 



