W. G. Van Name — Bermuda Ascidians. 329 



Botryllidae. 



Botrylloides nigrum Herdman, represented by three new sub- 

 species: concolor, planum, and sarcinum in addition to the 

 typical form. 



Symplegma viride Herdman. 



Polystyelid.ee. 



Michaelsenia tincta, n. sp. 

 Diandrocarpa botryllopsis, n. sp. 



SIMPLE ASCIDIANS. 



Halocynthiid.se. 



Polycarpa obtecta Traustedt. 



Styela partita (Stimpson) var., bermudensis, now 



Halocynthia rubrilabia Verrill. 



Halocynthia riiseana (Traustedt) var., munita, nov. 



Microcosmus miniatus Verrill. 



Ascidiidae. 



Ascidia atra Lesueur. 

 Ascidia cur rata Traustedt. 



The writer does not believe that this list by any means exhausts 

 the number of forms really found there. The collections were made 

 during the spring months. Collecting at other seasons would prob- 

 ably result in finding new species and larger and better specimens of 

 many of those which are here described. Moreover, different 

 methods of collecting might further increase the number. 



A few words in defense of the somewhat appalling number of 

 new species (21) are probably called for. The writer believes that 

 our knowledge of certain families, notably the Didemnida?, Halo- 

 cynthiidsB, and Botryllidae, has been retarded rather than advanced 

 by the practice of many authors of describing as a new species 

 nearly every faded and shrunken specimen that comes into their 

 hands, because it cannot be made to agree perfectly with descrip- 

 tions of other authors, made in many cases from similarly poor and 

 scanty material. Such specimens had far better be left undescribed, 

 unless they present characters so marked, that there is not likely to 

 be much difficulty in identifying the form again, and characters of 



