BRYOZOA OF WOODS HOLE REGION. 209 



In the inner waters there are about 12 species not represented in the outer waters, 

 viz: 



Loxosoma davenporti. 



Loxosoma tninuta. 



Barentsia discreta. 



Bugula flabellata. 



Membranipora lacroixii. 



Lepralia pallasiana. 



Flustrella hispida. 



Alcyonidium verrilli (A. ramosum Verrill non Lamouroux). 



Amathia dichotoma. 



Anguinella palmata. 



Hippuraria armata. 



Hippuraria elongata. 



This leaves more than one-half of the number of species common to both the inner 

 and outer waters. 



Comparatively few of our species show a preference for any special habitat. 

 Loxosoma davenporti lives as a commensal in worm tubes, and L. minuta in the same 

 way on Phascoleon strombi living in dead gastropod shells. Hippuraria elongata is also 

 a commensal living in the branchial chambers of the blue and spider crabs and on the 

 carapace of Pinnixia living in the tubes of Cluztoptcrus pcrgamentaceus. The last con- 

 dition offers a case of double symbiosis. Flustrella hispida occurs only in shallow 

 water along shore where it encrusts Fucus, etc. Membranipora tehuelcha occurs only 

 on the gulf weed (Sargassum bacciferum) drifted into our region from the Gulf Stream. 



The majority of our species are rather small, yet some of the erect chilostomes 

 form bushy colonies several inches in height. Conspicuous among these are Bugula 

 turrita and Gemellarialoricata. The semi-erect Porella proboscidea grows on the stems of 

 Roltenia and Sertularidae to a length of several inches and rises frill-like to a height of at 

 least ^ inch. A number of the encrusting species may cover an area of several square 

 inches. One of the most massive of these is Schizoporella unicornis. I have one speci- 

 men, from the piles of the United States Fisheries dock at Woods Hole.which measures 

 ii by 5 inches in extent and is over ]4 inch in thickness. Smittia trispinosavar. nitida 

 also forms nodules, sometimes as large as one's fist, encrusting shells or pebbles. Such 

 a crust consists of many layers of zooecia, the ones underneath being but the dead 

 skeletons of former generations. Of the ctenostomes, Alcyonidium -verrilli is the only 

 one in our region to attain a considerable size. The largest I have seen were about 6 

 inches high, the fleshy fronds making a good-sized mass. 



While the Bryozoa yield no useful products and thus have no direct value in com- 

 merce, they play a part, like most other small marine animals, in furnishing food for 

 fishes. I have seen large nodules of Schizoporella and Smittia taken from the stomachs 

 of sharks, while among our edible fishes the examination of such species as the "cunner" 

 (Tautogolabrus adspersus) and "blackfish" (Tautoga onitis) indicates that the various 

 Bryozoa often form no inconsiderable part of the diet. 



The list submitted in the following pages is probably fairly complete for the region, 

 though no doubt other species will be added from time to time by close collecting and 

 especially in unusual habitats. Many species are so minute that it is difficult not to 



