338 



BULLETIN OF THE BUREAU OF FISHERIES 



and 6 a. m., corroborating his view that T. catharina comes to the surface most often 

 by night. 



As a rule, Tomopteris has been represented in our hauls by large adults or 

 medium-sized specimens 15 to 40 millimeters long, with from 15 to 21 parapods, 

 and Doctor Huntsman informs me that he has invariably found this to be the case 

 in the Bay of Fundy. But during our August cruise of 1913 we took a considerable 

 number of its young in the northern and western parts of the gulf, including speci- 

 mens as small as 4 to 8 millimeters in length, with only 6 to 8 parapods (but identi- 

 fiable as this species by the tail, already visible, and by the number and location of 

 the rosette organs), at about the stage figured by Apstein (1900, pi. 10, fig. 2), as 

 follows : 



Locality 



Station 



Number 

 of speci- 

 mens 



Stage of development 



Oerman Bank 



Northeast corner off Grand Manan. 



North of Cashes Ledge 



Near Mount Desert Island 



Off Ponobscot Bay.. 



Eastern basin 



Off Penobscot Bay 



Off Cape Elizabeth 



10095 

 10097 

 10089 

 10099 

 10101 

 10093 

 10091 

 10103 



15 to 18 miles southeast from Chatham, Cape Cod. 



(') 

 1 

 2 

 2 

 2 

 1 

 1 

 0) 



(') 



6 millimeters upward, 8 to 12 parapods. 



6 millimeters, 12 parapods. 

 8 and 11 parapods. 



10 millimeters, 12and 14 parapods. 



Do. 

 5.5 millimeters, 13 parapods. 



7 millimeters, 11 parapods. 



4 millimeters upward, 6 parapods and 



upward. 

 6 millimeters upward, 8 to 14 parapods. 



1 Several. 



Judging from the early stage in development represented by these specimens, 

 it appears that T. catharina reproduced itself in some numbers in the Gulf of Maine 

 during the summer in question, proving that it is actually endemic there and not 

 restricted as a breeder to more northern seas. Although young specimens have 

 not been detected in our tow nettings before or since at any season (evidence that 

 it would be quite exceptional for Tomopteris to breed in any abundance within the 

 gulf), what little reproduction does take place there may be enough to maintain 

 the rather sparse stock of this worm. 



Of course, this does not negative the possibility that more or less immigration 

 takes place into the gulf from the north (p 339) ; but the distribution of T. catharina 

 in eastern Canadian waters, as outlined by Huntsman (1921), suggests rather that 

 the Gulf of Maine colony is to some extent isolated and separated from the more 

 abundant stock of this worm in Newfoundland waters and in the region of the Lau- 

 rentian Channel by a considerable gap, for it was taken at only one station inside 

 the continental edge along Nova Scotia by the Canadian fisheries expedition of 

 1915. Our scanty data point to an early summer breeding season, which agrees 

 with Southern's (1911) discovery — based on the occurrence of females with eggs 

 as well as of young — that it breeds from May until August in Irish waters. 



Relation to temperature and salinity. — The highest temperature in which we 

 have positively established the presence of T. catharina in the Gulf of Maine is 14.44° 

 (surface haul, Station 10245, August 12, 1914), and the great majority of captures 

 have been from water colder than 8°. At the other extreme it has been taken in 



