182 THE ROYAL SOCIETY OF CANADA 



Most of the measurements were made after the species were cleared 

 in oil of cedar-wood, and in no case was an individual, compressed 

 for the purpose of getting a better view of the internal anatomy, used 

 as a subject for such drawings or measurements. 



I wish to here express my indebtedness to the Biological Board of 

 Canada who, by placing means and equipment at my disposal, have 

 made this work possible. 



Species from Marine Fishes. 



1. Micropharynx parasitica Jagerskiold. 29, pp. 359-61. 



On the skin of the dorsal surface of Raja laevis (Mitchill), Barn- 

 door Skate. 



A Triclad Turbellarian. Appear as white oval flakes, ranging 

 in size from very small specimens just visible to the naked eye to 

 those attaining a length of ten millimetres ; quite difficult to detach 

 without injuring the posterior end. 



2. Dactylocotyle denticulatum (Olss.). 19, p. 10. 



Gills of Pollachiiis virens (L.), Pollack. 



One specimen from a small pollack from St. Mary Bay, Nova Scotia. 



3. Microcotyle poronotiy[?icCa\\viïn. Figs. 1-5, PL I. 



Gills of Poronotus triacanthus (Peck), Dollarfish. St. Mary 

 Bay, N.S. 



Body about 4 mm. in length, or about 2-8 mm. exclusive of the 

 caudal disc, somewhat stout, thick and spindle-shaped from a dorsal 

 or ventral aspect (Fig. 1), symmetrical. Breadth opposite the genital 

 atrium about 0-4mm. and at the widest part, which is at the middle 

 of the worm, 1.0mm. Caudal disc or sucker-bearing portion occupies 

 the posterior two-fifths of the body, projects slightly forward ventrally 

 (Fig. 2) and is provided with suckers varying in number, in most 

 specimens at hand, from 35 to 45 pairs, although one specimen, some- 

 what larger than the others, shows 63 pairs. The individual suckers 

 are from 0-085 to 0- 105mm. in breadth. Anterior sucker 0-10 long 

 by 0-05mm. wide and with a membranous septum which, being low, 

 does not completely divide the cavity into two parts. Three groups 

 of "sticky glands" almost in a straight line ahead of the mouth- 

 opening. Oesophagus terminates behind the genital opening where 

 it forks into the two main intestinal trunks. These send out numerous 

 lateral branches both inwards and outwards, the former simple and 

 the latter branching once or twice, but all almost completely obscured, 

 in transparent preparations, by the vitelline follicles. The main 

 trunks seem to terminate within the body proper; at least they could 

 not be traced with certainty beyond the posterior end of the group of 

 testes on account of the fact that, since all material at hand was 



