2IO BULLETIN OF THE BUREAU OF FISHERIES. 



overlook them. As previously stated, our list contains 8i species besides several varie- 

 ties which often appear as species in other lists. Whiteaves list for eastern Canada 

 contains 115 species (46 of these occur also at Woods Hole); the Plymouth, England, 

 list contains 103 species, while Herdman lists 136 in the Irish Sea. It must be remem- 

 bered, however, that all these regions are not only considerably larger in extent than 

 ours, but that the depth has a greater range. On the other hand, Levinsen's list in the 

 "Zoologica Danica" includes only 68 species for all Denmark, and Graeffe's list for 

 Triest but 56. By comparing these lists and taking into consideration the uniform 

 conditions of depth, temperature, and salinity in our region it will be seen that our 

 Bryozoa fauna is a fairly representative one. 



In the classification which I have adopted our 81 species are included in 36 genera, 

 and these in 20 families. The Endoprocta are represented by 5 species included in 2 

 families and 3 genera. The Ectoprocta are well represented in the 3 suborders of 

 the order Gymnolsemata as follows: Cyclostomata, 8 species belonging to 4 genera and 

 3 families; Chiloslomata, 55 species in 21 genera and 10 families; Ctenostomata, 13 

 species in 8 genera and 5 families. 



To bring together in convenient form the widely scattered descriptions of our 

 Bryozoa I have given under each species a rather full diagnosis of the species as it exists 

 in our region. In making out such descriptions I have often drawn largely from the 

 original published sources, where these were satisfactory, and I have amplified or abbre- 

 viated or otherwise modified these as the conditions required. In the case of Vesicularia 

 familiaris listed by Verrill, but which I have not seen, I have been compelled to copy 

 from other sources without making a comparison. 



For the convenience of the student I have also included keys of families, genera, and 

 species. Because of the brevity of such diagnosis the keys must necessarily be more or 

 less unsatisfactory and must be constantly checked up by a perusal of the descriptions and 

 reference to the figures. It must be borne in mind that the form of the colony is generally 

 of little use in determining the species, owing to the great amount of variation in this 

 respect. It must also be noted that a great deal of variation is exhibited in the amount 

 and form of the calcification of the individual zooecia, especially among the encrusting 

 chilostomes, and the same is true of the form and occurrence of avicularia, spines, and 

 other secondary structures. In the soft-bodied endoprocts and ctenostomes the form of 

 the body depends largely on the amount of contraction. I can testify, after a number of 

 years work, that the group is by no means an easy one for the beginner, and I know of no 

 other in which the student is more likely to be misled by superficial resemblances. 



Many of our Bryozoa have never been adequately figured, some not at all. Those 

 which occur also in Europe have been illustrated, but, aside from Hincks' " British Marine 

 Polyzoa," now long out of print, the figures are badly scattered and often are not easily 

 accessible to the general student. To cover this deficiency and to bring together the 

 illustrations of our species, I have figured anew all the forms dealt with in the following 

 list. With the exception of six species all the figures are drawn from local specimens, 

 and at least have the merit of representing the forms as they occur in this region. Nearly 



