606 PRor. w. A. heedman's eeyised 



Stmpxegma, Ilerdman, 1886. 



Colony stalked, consisting of several ovate ascidiaria* connected 

 by branched peduncles. 



Ascidiozooids moderately large, not mucb elongated, and not 

 divided into regions. 



Test firm, vessels numerous. 



BrancMal sac large and well developed, provided with internal 

 longitudinal bars. 



Dorsal lamina in the form of a plain membrane. 



Alimentary canal and gonads forming a mass projecting for a 

 short distance only behind the branchial sac. 



This genus, which I placed in 1886 in the family Distomidse on 

 account of tbe close resemblance of the colony to that of a Colella, 

 I now agree with Lahille had better be transferred to the Botryl- 

 lidae. The Botryllid affinities, as I pointed out in the original 

 description, are very marked, although Symplegma differs more 

 from the other four genera of Botryllidse than these do from one 

 another. 



There is only one known species, Symplegma viride, Herdm., 

 from Bermuda. 



BoTETLLTTs, Gartner 6f Fallas, 1774. 



Colony thin, incrusting. 



Systems circular or stellate. 



Ascidiozooids ovate, with their apertures placed far apart. 



Test soft and gelatinous, never much thickened. 



Branchial sac large, with 3 internal longitudinal bars on each 

 side. 



Viscera alongside the branchial sac, at its posterior end. 



This genus contains a very large number of species which are 

 very difficult to distinguish. In fact, species do not appear to 

 be at all clearly differentiated ; and, to add to the difficulty, many 

 of the descriptions are very imperfect and only take account of 

 external characters wbicb cannot be applied to preserved spe- 

 cimens. 



The following is a list of the species of JBotryllus. In the pre- 

 sent state of our knowledge of these forms I feel that it is useless 

 to attempt to distinguish them by brief characters in tabular form. 

 Some of these species have several marked varieties, and most 

 are very variable. 



* That part of the colony in which the ascidiozooids are placed. 



