BIGELOW: EXPLORATIONS IN THE GULF OF MAINE. 121 



Thus it was inhabiting rather warmer water than Clione (47°-52° 

 as against 41°-57°), but of about the same salinity; and the capture 

 at Station 30, on the surface, is particularly interesting, because 

 Salpa fusiformis was likewise taken at that Station. The other cap- 

 tures of Limacina were in open nets from 20-30 fathoms. Unlike 

 Clione, the specimens were of various ages; a swarm of small ones 

 being taken at Station 19, the largest at the last Station at which it 

 occurred, i. e., 40. This suggests that its chief period of growth is 

 July and August in the Gulf. 



Salpae (Plate 5). — Salpae were observed over only a small area, 

 from Station 30 to Station 31; several S. fusiformis being taken at 

 each Station, and others seen floating on the surface. But a large 

 haul of S. mucronata was made twenty-five miles off Chatham, on the 

 surface, September 30, by Capt. John McFarland of the fishing 

 schooner Victor. The geographic importance of these hauls has been 

 noted (p. 107). 



Tomopteris helgolandica. This is the only species of the genus 

 encountered, and was taken at Stations 11, 14, 30, 32, 40, 42, and 44, 

 i. e., in Massachusetts Bay, north of Cape Ann, off Cape Porpoise, 

 off Mt. Desert, on German Bank, off Seguin, and once in the Kennebec 

 River. It was not taken in any of the off-shore hauls. The known 

 salinities and temperatures are: — 



Station 30 surface temperature 52° salinity 32.7%o 



Station 32 surface temperature 57° salinity 32.5%o 



The other captures were in open nets from considerable depths (20- 

 60 fathoms). 



Chaetognaths. — Sagittae were taken in greater or less numbers at 

 almost every station. But the determination of most of the species 

 of this genus is so difficult that only four, Sagitta serratodentata, S. 

 elegans, S. lyra, and Eukrohnia hamata have been selected, as being 

 so easily recognized that the records can be depended upon. And 

 the identifications of these have been verified by Mr. E. L. Michael. 

 Sagitta serratodentata, especially, is a useful index-species, because the 

 serrate margins of its jaws separate it from all its allies. Among the 

 Sagittae in the Grampus collection it is likewise readily identified by 

 its stiff, slender body, and very large spermaries. 



Sagitta serratodentata (Plate 5) was taken at Stations 19, 21, 22, 23, 

 25, 27, 28, 30, 31, 32, 33, 36, 38, 40, 41, 44, but not in any of the bays 

 or harbors, or in the Grand Manan Channel. The list of stations 

 shows that it occurred very generally over the Gulf, i. e., in Massa- 



