66 



Caligus curtus, Miiller. — On October 30th, 1917, two codling, 

 about 18 inches long, were brought into the Laboratory, and 

 from their heads eight specimens of Caligus were removed. Seven 

 of these were females, with an average length of 8-1 mm. Five 

 of them bore complete egg-strings, which averaged 9-6 mm. long. 

 The remaining individual measured 11 mm. in length, and was a 

 male. The copepods were quite active after removal from their 

 host, and were observed to bear large numbers of white leech-like 

 creatures round the edge of the carax^ace, and large bunches of 

 club-shaped objects at the end of the body on the ventral surface. 



In colour the}^ were pale yeUow and profusely patterned with 

 dark red irregular-shaped chromatophores, especially along the 

 edges of the carapace. None of the specimens showed any blood 

 in the alimentar}^ canal. 



It was not without some difficulty that the species was finally 

 decided upon, as the creatures bore considerable resemblance to 

 both C. rapax and C. curhis. In the general form of the 

 body the females correspond very closely to that of C. rapax, 

 while the greater size, and the length and general character of the 

 egg strings are decidedly those of C. curtus. Also the male exceeds 

 the female in size — another characteristic of C. curius — but does 

 not do so to such a marked extent as stated by C. B, Wilson.* 



Working from Wilson's descriptions and arranging the char- 

 acters of our specimens in two colurq^ns according to their likeness 

 to one or other of his species, we get the following : — 



C. curtus. C. rapax. 



Carapace longer than wide. 

 Anterior margin only slightly 



rounded. 

 Lunules large, orbicular, widely 

 separate and projecting. 

 Eyes small, situated forward. 



Setae and spines present on first First antennae large, tips nearly 

 antennae. equal extreme width of carapace. 



Length of female = 8-1 mm. (8-12 mm.)* 

 Length of egg strings = 9*6 mm. (14 



mm. ) * 

 Longth of male — 11 mm. (13-20 mm.)* 



*■ Tlie numbers in brackets denote Wilson's measuiemcnts for C. curtus. 



From the table it is evident that these mdividuals had affinities 

 with both the above-mentioned species, but I have decided to 



* Chas. Branch Wilson. *' Parasitic Copepodj oi North Amei'ca." 



