88 
of the Long Rough Dab in the snmmer and early antumn. I have 
not succeeded in finding it in the winter months. 
mtmum fem (Olsson). This Trematode occurred in the gaU 
bladder of every specimen of the Catfish examined I ^ers'and 
that Mr. Nicoll, of St. Andrews, M about ™*j£%£Z 
work on this species, and also on a new spec.es of All ocreadmm, , o 
a close ally of this genus, which also occurs m the Catfish of our 
cott in four out of a dozen specimens. For tins reason I shall 
not describe these species here. 
Gends— Podocotyle (Dujardin). 
Pclocotylc atomon (Kud.) (Plate I., fig. 8.) Odlmer, « Fauna 
Arctica," page 820. 
The svnonvmy of this species is discussed by Odhner at length. 
It applrs to be not so common on the Northumberlana coast as 
it is at St. Andrews, where Niooll* found rt "ntly m the 
small fish of the rock pools. I have only found ' » ™ 6 ^ 
™ the Bull-Head and the Plaice. Apparently it has not beioie 
been tcold from the latter fish, but only one specimen wa 
J sent in it. The Bull-Head, CoUus is, however, one of 
L commonest hosts in Greenland (Levmsen), Sweden (Odhner), 
and Britain. It has been recorded also from many other fish. 
The "orm occurred in the pyloric caeca and intestine of two 
specimens of the Bull-Head out of thirteen examined, several in one 
specimen (August), and one in the other (February), 
^specimens varied from 1-9 to 3-5 m.m. iu length, and agree 
verv well with Odhner's description of P. atomon as restricted by 
Ihat author. The body is elongated, colourless, very g transparent 
and unarmed. The anterior sucker (m specimen 2-5 mm. long) 
measures CH6 mm. across; ventral sucker, 0-8 mm. across, and 
7a ed far forward. There is a small P^T^tTleS 
pharynx, and an oesophagus rather more than double the leu th 
of the pharynx. The fork of the intestine is just in front of the 
vfntol ZL, and the intestinal lobes reach to the posterior end 
of tl e body. The excretory vescicle is a simple long sac reachnig 
to lue o/ary, where it widens slightly and gives off two laterd 
vessels. It lies dorsally, and terminates in a posterior poie. xne 
els are ventrally placed, one in front of the other with a smaU 
space between, and some way from the posterior eiA FiomjacU 
* Op. eit, page 73. 
