PLANKTON OF THE GULF OF MAINE 377 



Steplianomia cara (A. Agassiz) 



Although this siphonophore is widely distributed in the gulf both in time and 

 in space, we know little more of its natural history or of its status in the economy 

 of the plankton than when Alexander Agassiz (1865) first recorded and beautifully 

 pictured young specimens of it from Massachusetts Bay; and although Fewkes 

 (1888) has since given a description and figures of the adult, it is still doubtful 

 whether the "S. cara" of northern seas is identical with or distinct from the "S. 

 bijuga" of warmer latitudes. Unfortunately our Gulf of Maine collections can not 

 settle this question, because these very delicate animals are usually battered almost 

 past recognition in the tow nets; but the presence of a spherical red or yellow oil 

 globule at the base of each palpon (a conspicuous character first described by Fewkes 

 and visible in the least damaged of the Gulf of Maine series) is apparently peculiar 

 to the northern cara, and since cara grows much larger than its warm-water relative, 

 besides differing from it in minor anatomical details, it probably deserves recogni- 

 tion as a distinct species. The relative ranges of the two — cara and bijuga — are 

 consistent with this, for while S. cara is common in the Gulf of Maine " we did 

 not find it along the coast south or west of Cape Cod during the summers of 1913 

 or 1916, the autumn of 1916, the winter of 1914 (Bigelow, 1918), or in February of 

 1920. On the other hand, the southern bijuga is not known to occur north of Key 

 West in the western Atlantic, which leaves a gap of something like a thousand 

 miles between the southern limit of the one and the northern limit of the other, as 

 now known. Similarlj 7 , there is a long gap between the most southerly known 

 record of the northern and most northerly record of the southern race or species in 

 the eastern Atlantic. 



Just what relationship the S. cara of North American waters bears to the Arctic- 

 boreal Steplianomia of the northeastern Atlantic is also uncertain, no detailed account 

 having appeared of the specimens most recently recorded thence (Sloan, 1891; 

 Browne, 1900); but probably the two are identical; in fact, it would run counter 

 to all our experience of the northern pelagic fauna as a whole to find them otherwise. 



During our recent cruises we encountered Steplianomia in the months of 

 January, March, July, August, September, and December, and at the various locali- 

 ties indicated on the chart (fig. 103), but it is not safe to base a definite statement 

 of its status in the gulf on these records, both because it is decidedly erratic in its 

 occurrence and because its bells are so fragile that they are apt to be battered past 

 recognition by the other plankton taken with them in the tow nets. 



Steplianomia may usually be found in one part of the gulf or another during 

 the summer months, but it can not be very generally distributed at that season, 

 for we have never taken it at more than a small percentage of our stations during 

 any one summer's cruise. In 1913, for example, it was detected at three stations 

 only, once, however, in abundauce (p. 19; station 10058). There are only four 

 records of it in the July and August towings of 1914; none for 1916. If the years 

 1920 and 1921 can be taken as representative, it is decidedly more abundant and 

 widespread during the winter, for it occurred at about half our December and Janu- 



il Some long-stemmed physophore, and probably this species, ranges northward as far as Lady Franklin Bay on the west coast 

 of Greenland (Fewkes, ISSfea) and to Robeson Channel (Moss, 1878). 



