BRYOZOA OK WOODS HOLE REGION. 211 



all the figures have been drawn by myself, but figures 15, 30, 30a, and 39 are the work of 

 my wife. I must make special acknowledgment for the work of Mr. Howard J. Shannon, 

 who has so faithfully portrayed TubuHpora atlantica, T. flabellaris, and T. lUiacea. These 

 figures were drawn under my direction, so I can vouch for their accuracy of detail, but 

 their artistic merit is due entirely to Mr. Shannon's skill and patience. 



For the systematic study of the group Hincks' "British Polyzoa" still remains the 

 standard work for North Atlantic species, and is indispensable to the special student. 

 It covers slightly more than half of the species of our region. Hincks' three papers on 

 the "Polyzoa of the St. Lawrence" and Smitt's "Floridan Bryozoa" will also be found 

 most useful in comparison for Atlantic species, and Dr. Alice Robertson's valuable 

 papers (Proceedings California Academy of Science) for Pacific coast species. In the 

 appended bibliography all papers have been listed which contain either the original 

 descriptions or a reference to the occurrence of our species on the Atlantic coast. 



The literature on the general structure of the Bryozoa is fortunately more accessible 

 than that dealing with the systematics of the group. Reference may be made to the 

 article by Harmer in the Cambridge Natural History, or for more extended study, to 

 Calvet's "Bryozoaires Ectoproctes marins." 



It is scarcely necessary to mention the fact that such changes have been made in 

 the classification and nomenclature of the Bryozoa since the appearance of the earlier 

 papers that many of the species recorded therein are quite unrecognizable except to the 

 special student familiar with the synonymy. I have tried to give a complete synonymy 

 in each case of all the references to the species in American waters. It might also be 

 taken for granted that many errors in identification would be found to occur in these 

 papers. Our knowledge of the Bryozoa is at present none too well organized, but 40 or 

 50 years ago it was in an extremely chaotic state. For this reason it is not possible to 

 make absolutely certain of the synonymy in all cases, but by obtaining material from the 

 original localities some doubtful cases have been decided with a fair degree of certainty. 

 Prof. Verrill has aided me very materially in this matter by kindly permitting me to 

 examine his collection of mounted slides of specimens determined by himself and by 

 Packard, Stimpson, and Dawson. The Canadian Geological Survey, through the 

 kindness of Mr. Lawrence M. Lambe, has lent me much identified Canadian material for 

 comparison. Dr. S. F. Harmer and Dr. O. Nordgaard have supplied me with many 

 European species. As a result, in the case of nearly all species which occur in other 

 waters, I have been able to make direct comparisons with material from the regions 

 where the species are already well known. 



Class BRYOZOA Ehrenberg (POLYZOA, J. V. Thompson). 



Minute animals forming colonies (with rare exceptions), asexual reproduction by budding devel- 

 oped to a high degree. A retractile crown, the lophophorc, which bears ciliated tentacles, a U-shaped 

 alimentary canal, a simple nerve ganglion; coelom present, but vascular system wanting. 



Subclass ENTOPROCTA — Anal opening situated within the lophophore; coelom greatly reduced; 



tentacles rolled inward in contraction. 

 Subclass ECTOPROCTA — Anal opening situated outside the lophophore; coelom well developed; 

 the whole lophophore withdrawn in contraction. 



