78 



BULLETIN OF THE BUREAU OF FISHERIES. 



III. Average number of species per dredge haul for the two vessels and the two bodies of 

 ■water considered separately. 



Fish Hawk stations. 



Vineyard 

 Sound 

 (77). 



Buzzards 

 Bay (90). 



Porifera 



Hydrozoa 



Actinozoa 



Nemertinea. . . . 



Bryozoa 



Asteroidea 



Ophiuroidea . . . 

 Echinoidea .... 

 Holothuoridea . 



Annulata 



Sipunculida. . . 



Cirripedia 



Amphipoda 



Isopoda 



Decapoda 



Pycnogonida. . 



Pelecypoda 



Amphineura. . . 

 Gastropoda. . . 

 Cephalopoda. . . 



Tunicata 



Pisces 



The Crab Ledge Bryozoa have not been listed by stations. 



In a similar way we have represented the wealth in species of each of the types of 

 bottom which have been distinguished (see p. 70). 



IV. Average number of genera and species per dredge haul for the three types of bottom. 



Genera. Species. 



Sand (170) 33. 6 36. 5 



Gravel and stones (167) 35. 3 38. o 



Mud (112) 34-8 37. 2 



While there is here, likewise, a rather surprising uniformity among the figures, it is 

 to be noted that the number of species is greatest for the stony bottoms and least for the 

 sandy ones. 



