BIOLOGICAL SURVEY OP WOODS HOLE AND VICINITY. IO3 



Desor, in 1848, described two species of Bryozoa (Bugula turrita and Membranipora 

 tenuis) which were collected by him in the vicinity of Nantucket. 



Verrill, in the report upon the invertebrates of Vineyard Sound, listed 33 species of 

 Bryozoa, of which 27 determined species and several doubtful ones were recorded for 

 specified points within the limits of the Woods Hole region. Only one of our local species 

 was there described for the first time. In subsequent papers Verrill added a consider- 

 able number of new Bryozoa to the fauna of the deeper waters off the American coast, 

 but not more than 5 of these last fall within the limits embraced by the present report. 

 Nickerson (1898) added a single species of endoproct (Loxosoma davenporti) to our 

 local fauna, this being first described from specimens taken by him at Cotuit Harbor. 

 So far as we know this is the only addition which has been made to Verrill's lists of 

 Bryozoa down to the time of the present Survey. 



Whiteaves catalogues 1 1 5 species of Bryozoa for the waters of eastern Canada. Of 

 these species, 45 ( + 2 ?), or about 40 per cent, have been recorded from the Woods Hole 

 region. On the other hand, these 47 species which are common to the two lists 

 constitute nearly 60 per cent of the number comprised in our own catalogue. 



The Plymouth list records the occurrence of 103 (+1 ?) members of this group, a 

 number which is also considerably in excess of that recorded for the Woods Hole region. 

 About 30 per cent of the Plymouth species (about 40 per cent, therefore, of the Woods 

 Hole species) are common to the two lists. 



Herdman catalogues 136 species of Bryozoa (along with many varieties) for the 

 Irish Sea; while Graeffe has recorded 56 species for the Gulf of Triest. 



It is scarcely likely that these figures give us any accurate idea of the relative rep- 

 resentation of this phylum in the respective areas of sea bottom. It is not at all prob- 

 able that the search for these organisms has been equally exhaustive at the various 

 points named, and it is certain that the areas explored are far from being comparable in 

 magnitude (see p. 87). We may assert in full confidence that the extension of our own 

 dredging operations to the 50-fathom line would have very greatly increased our list of 

 Bryozoa. 



The average number of species per dredge haul recorded for the stations of the 

 regular series was 2.9. The species having the most general distribution was Bugula 

 turrita, which was present at 255 (more than half) of the dredging stations. Those 

 which were encountered so frequently as to be taken at one-fourth or more of the total 

 number of stations are : 



Bugula turrita (255 stations). 

 Crisia eburnea (201 stations). 

 Schizoporella unicornis (197 stations). 

 Smittia trispinosa nitida (163 stations). 



Representatives of this group are to be found attached to almost every sort of solid 

 object within the waters of our region. Upon stones and shells they form calcareous 

 incrustations, which may be white, gray, yellow, or red in color, and are often many 

 layers in thickness. Such are Smittia trispinosa nitida and various species of Schizopo- 

 rella, Membranipora , and Lepralia. 



Other calcareous forms (Cellepora americana, Schizoporella unicornis, and 5. biaperta) 

 give rise to coral-like nodules or foliaceous expansions upon Hydrozoa, algae, or other 

 Bryozoa. Erect, hydroid-like colonies, such as those of Bugula, Bicellaria, or Crisia, 



