* 



122 The Ottawa Naturalist. [Jan. 



extend into its jointed limbs, and thus form a most elaborate 

 network for absorbing the fluid nutriment from its host. The 

 bunch of roots may form a compact matted mass in Peltogaster. 

 The crab, though apparently incommoded by this fleshy bag 

 attached to its body beneath, seems not to suffer greatly, but 

 it does not grow much, as moulting of the hard shell is arrested. 

 "Fortunately," says Dr. Arthur Shipley, " Sacculina appearsto 

 live only three years, and when it dies the crab resumes its 

 growth," but some recent researches by Mr. C. G. Robson point 

 to the death of the crab in some cases, owing to starvation; 

 the fatty materials left being insufficient for its necessities. 

 Professor Giard found in the helmet crab (Stenorhynchus) that 

 the penetration of the cirripe de-parasite caused the destruction 

 of the ovaries and the sperm aries. In the latter event, the male 

 crab assumes some of the features of the female and exhibits a 

 broader tail and smaller pincer claws; but in the female crab, 

 the abdominal feet become smaller in size as in the normal male. 

 The studies of Dr. Geoffrey Smith show, on the other hand, that 

 more yolk-forming material (as in a female crab about to spawn) 

 results in a crab with Sacculina attached; and Mr. Robson found 

 an excessive production of fat in the liver and blood in affected 

 crabs of both sexes, resembling the condition of the male when 

 about to cast his shell ; or, in the female, resembling her condition 

 when maturing her eggs before depositing them. 



It has been reserved for Mr. Potts, a Fellow of Trinity Hall, 

 Cambridge, who came over from England, early in 1911, to 

 pursue marine researches at the Dominion Biological Laboratory, 

 Departure Bay, near Nanaimo, B.C., to discover a new Cirripede, 

 which surpasses all previously described species in its strange 

 structure and life history.* Mr. Potts' main purpose was the 

 study of the Annelids of the Pacific, and his investigation of 

 this new parasitic Cirripede was a subsidiary piece of work, 

 and abundantly shows what interesting original discoveries 

 await biological students who will spend a season or two at any 

 of the Biological Stations of Canada. 



Called by Mr. Potts Mycetomorpha vancouverensis, this new 

 species, for which indeed a new genus Mycetomorpha had to be 

 established, appears as a fungus-like sac on the under-side of 

 a Pacific shrimp (Crangon communis, Rathb.), close to the basal 

 joints of the abdominal limbs. (Figs. 1 and 5). In form it is 

 an elongated sac, in. long and i in. wide, and beset along 

 the margin by crowded club-shaped lobes, over fifty in number. 

 (Fig. 1 /.) The sac is very thin-walled, a delicate muscle-layer 

 being indicated by faint striations, through which the round 



* See Mr. Potts' paper in Spengel's Zooloejisch, [ahrb. 1912, pp. 575-594, 

 1 Pis. 



