November, 1920] ThE CANADIAN FiELD-NaTURALIST 



ARGULIDAE FROM THE SHUBEN ACADIE RIVER. NOVA SCOTIA. 



149 



By Charles Branch Wilson, Ph. D., State Normal School, Westfield, Mass., U.S.A. 



A survey of the Shubenacadie river, which 

 empties into the Basin of Minas, Nova Scotia, was 

 recently made by Mr. A. H. Leim in connection 

 with the Canadian shad fisheries. During this sur- 

 vey many specimens of both young and adult 

 argulids were obtained at Shubenacadie with the 

 tcw-net in tidal water which seemed to be fresh 

 rather than sail. 



These specimens were sent to the present author 

 for identification, and they proved to contain an 

 abundance of both sexes of two species of Argulus, 

 cne of which had previously been found in many 

 localities on the Atlantic coast farther south, while 

 the other was new to science. The following record 

 of these two species is herewith submitted. 



Argulus alosae Gould. 



Argulus alosae Gould, Invertebrata of Massa- 

 chusetts, 1841, p. 340, text figure: S. I. Smith, 

 Report U. S. Com. Fish and Fisheries, 1872, p. 

 575 (281): R. Rathbun, Proc. U. S. National 

 Museum, vol. 7, 1884, p. 485: J. F. Whiteaves, 

 Cat. Marine Invertebrata cf Eastern Canada, 1901, 

 p. 216: C. B. Wilson, Proc. U. S. National 

 Museum, vol. 25, 1902, p. 707, pi. 12; pi. 26, 

 fig. 80. 



Record of specimens. Ten specimens, including 

 both sexts, were obtained August 1, 1919, at 8.45 

 p.m.: two males were obtained on the same date 

 at 9.10 p.m.: a single male was obtained July 21, 

 at 6.15 p.m. 



Reniarl^s. This species was doubtfully recorded 

 by Mr. J. F. Whiteaves in the reference given above 

 as attached to Casierosteus hiaculeaius Shaw, and 

 other small fishes taken off Pictou island in the 

 Gulf of St. Lawrence. All the other recorded lo- 

 calities are much farther south. The present record 

 substantiates that of Whiteaves and fully establishes 

 the species in Canadian waters. Again it has 

 hitherto been found only upon fish hosts in salt 

 water; the present specimens were captured in a 

 tow-net in fresh water. Their presence in the tow 

 makes it certain that they infest fish in the immediate 

 vicinity, and it may be that they will be found some 

 day upon the shad whose name they bear. 



Argulus piperatus, new species. 

 Record of specimens. Twenty-two specimens, 

 of which six were females and the rest males, were 

 obtained August 1, 1919, at 8.45 p.m. in company 



with the first lot of Argulus alosae. Another lot 

 of ten specimens, including both sexes, were caught 

 in the second towing, August 1 at 9.15 p.m. Five 

 males were cbtained July 31 at 9.50 p.m., and two 

 males on the same date at 10.10 p.m. The majority 

 of all these specimens were of small size although 

 sexually mature. But a few of them were large 

 enough to be regarded as fully developed adults, 

 and from these the following description has been 

 taken. 





Fig. 1. Dorsal view of Argulus piperatus, female. 

 The line represents a length of 1 mm. 



Specific characters of female. General shape 

 of the carapace elliptical, one-fourth longer than 

 wide, with shallow lateral sinuses and broad, well 

 rounded posterior lobes. Posterior sinus, one-third 

 the length of the carapace, with parallel sides; pos- 

 terior lobes just reaching the base of the abdomen. 

 Eyes far forward and well separated. 



Abdomen elliptical, one-fourth the length of the 

 carapace, the longitudinal and transverse diameters 

 in the proportion of 11 to 9; its posterior lobes 

 well rounded and inclined inward so that their 

 inner margins are in contact. Anal sinus 27.50*^^, 

 of the abdomen length; anal laminae basal, minute 

 and unarmed; sperm receptacles small, circular 

 and rather widely separated. 



