BIGELOW: EXPLORATIONS IN THE GULF OF MAINE. 103 



23 we found a single specimen of the medusa Tiaropsis diademata, 

 which is abundant in Massachusetts Bay in June. 



At Station 23 we first met Pleurobrachia pileus, and we frequently 

 took it later, further north and east; we saw Beroe cucumis on the 

 surface, and captured sticklebacks, and a large isopod (Idotea) from 

 floating Fucus. In these off-shore waters Sagitta serratodentata was 

 more plentiful than we had found it before, — a case treated at length 

 elsewhere (p. 121) and an occasional fragmentary agalmid was likewise 

 taken (p. 121) besides considerable numbers of fish fry. 



At Station 27 Calanus finmarchicus was taken in swarms at the 

 surface, the only time we found it abundant at that level, in the 

 day time, though it often was at night. Euthemisto was plentiful 

 at the off-shore Stations 29 and 31, and at the former we took one Tiara 

 pileata, and two Aglantha (40-0 fathoms), this being the first time the 

 latter was encountered during the cruise. On the other hand, we 

 found none of the typical shore forms, e. g., Aurelia, Cyanea, Meli- 

 certum; and over the Eastern Basin not even Staurophora, Phialidium, 

 Beroe, Bolinopsis, or Pleurobrachia, though the last three, of course, 

 are not dependent upon shallow water at any stage in development. 



German Bank proved interesting, for though the surface tempera- 

 ture was low (52°, Station 30) and the bulk of the tow consisted of 

 Calanus finmarchicus, with a few Euchaeta, Anomalocera, a large 

 number of the schizopod Euphausia, the amphipods Hyperia galba 

 and Euthemisto, Tomopteris helgolandica, Sagitta elegans, and S. 

 serratodentata, forming a typical boreal assemblage, the surface haul 

 also yielded two large Salpa fusiformis and two specimens of the 

 siphonophore Physophora hydrostatica. During the next day Salpae 

 were occasionally seen on the surface; and at Station 31 several were 

 taken in the tow, all S. fusiformis (p. 121). But here, as on German 

 Bank, the plankton as a whole was the same as we had found over the 

 Gulf as a whole, Calanus finmarchicus composing far the chief bulk of 

 the haul. This proved to be an interesting station, because the open 

 net from fifty-five fathoms brought back several specimens of the cold 

 water Chaetognath Eukrohnia hamata, a species found on the surface 

 in Arctic and Antarctic regions, but limited to the mesoplankton in 

 temperate and tropical latitudes. This same haul also yielded two 

 specimens of the large Sagitta lyra; and neither of these species was 

 taken again during the voyage. The list of copepods also received an 

 addition, Euchirella rostrata. After leaving this station we saw no 

 more Salpae. 



Twelve miles off Mt. Desert Rock, August 16, 3 A. M., we made a 



