BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY 191 



over a century. These men erred rather in the direction of discovering too many new 

 species than in ignoring well-established ones. 



The medusa, Gonionemus murbachii, does not seem to have been observed until 

 1894, when according to Perkins (1902) it "made an astonishingly sudden appearance 

 upon the scene." Yet at present this relatively conspicuous and readily recognizable 

 medusa is one of the most familiar objects of research in the Woods Hole laboratories. 

 Its distribution, locally, appears to be rather restricted, however, most of the collecting 

 for this species being carried on in one small salt-water pond. 



The large noncolonial hydroid, Tubularia couthouyi, whose conspicuous yellow 

 perisarcs are dredged with considerable frequency in Vineyard Sound, was likewise 

 not referred to in the report of Verrill and Smith, although this latter listed a number 

 of other hydroids which have not been noted by any subsequent observers. And it is 

 likewise somewhat astonishing that neither of our local species of Arenicola was men- 

 tioned in the Vineyard Sound report, although one, at least, of these immense annelids 

 is now common at points in the vicinity of Woods Hole. 



We can not attribute so much importance to the failure of previous writers to 

 record the gastropod Lacuna puieola, since this species, although very abundant, is like- 

 wise very small. The same may be said of a considerable number of other species 

 which are comprised in our list but were not recorded by various previous observers. 

 Inconspicuous or uncommon species may readily be overlooked, even by competent 

 collectors. Such an oversight seems unlikely, however, in the case of the other examples 

 cited above. 



Just the opposite state of affairs is to be noted in the case of certain species which 

 were recorded by Verrill as common in local waters, but which the present writers 

 have seldom or never met with. As a striking instance of this is to be mentioned the 

 anemone Edwardsia lineata Verrill, concerning which the last-named zoologist makes 

 the following entry (p. 739): "Vineyard Sound and off Gay Head, 6 to 12 fathoms, 

 among ascidians, annelid tubes, etc., abundant." A search in just such situations, 

 both by Prof. Hargitt and by ourselves, has failed to disclose a single specimen. The 

 size, as stated by Verrill (25-35 mm. long), makes it unlikely that the species has been 

 persistently overlooked by us. 



The barnacle Balanus crenatus was recorded by Verrill and Smith as "dredged 

 abundantly in Vineyard Sound." While we have found it to be common upon piles 

 at Vineyard Haven, we have never, with a few possible exceptions, encountered this 

 species with the dredge, either in Vineyard Sound or Buzzards Bay. This is true 

 despite the fact that practically all of the barnacles dredged by us were saved for 

 subsequent inspection. 



The crabs Libinia dubia and Panopeus [Eurypanopeus] depressus are of far less 

 general occurrence in these waters than the statements of Verrill and Smith seem to 

 imply. Although we have encountered both of these species in the shallow waters 

 near shore, we have not a single authentic record of either species having been taken 

 in the dredge during the course of our operations. 



While it is not likely that all of these discrepancies between earlier and later state- 

 ments can be attributed to actual changes in the occurrence of species, it is probable 

 that some of them are due to such changes. 



o It has just been learned from Prof. M. A. Bigelow that he noted the occurrence of this barnacle at Woods Hole in 1898. 



