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Calliobdella nodulifera (Malm 1863). 119 
I have examined the two specimens in the British Museum which are 
labelled Pontobdella littoralis, Johnston, since it is possible that the latter is 
Calliobdella sp., and probable that it is either Calhobdella nodulifera or 
Trachelobdella lubrica, Grube. One of these specimens recorded from 
Sukkertoppen, Greenland, as living on Laminaria (Holboll’s Coll.), does 
indeed resemble the species I am considering, but, as is only natural in a 
preserved specimen, no respiratory vesicles are visible. The pigment cells, 
however, under the low power of the microscope form a valuable clue. The 
other specimen, from 30 fathoms, off the coast of Greenland, is spoilt and 
unrecognisable as a leech. 
Synonomy.—I do not know whether this preference for the Gadide, which 
I have mentioned, influenced Johansson when he remarked that he con- 
sidered three species of Malm, viz. Piscicola crassicaudata, P. subfasciata and 
P. gracilis to be identical with Calliobdella (Piscicola) nodulifera. Let us 
consider what their claims are. In C. nodulifera, Malm saw the respiratory 
vesicles in series on both sides of the abdomen, and in his figure shows 
thirteen pairs. Unless he is mistaken on this point the animal he saw should, 
in my estimation, be placed in the genus Zvachelobdella. But in the other 
three species he says there are no respiratory vesicles. I will pass over this 
point considering it natural that they collapsed after death and so were 
invisible. The remaining characters are: 
P. crassicaudata.—Posterior sucker oval and almost double the anterior. 
Anterior sucker sub-elliptical. Body with irregular yellowish- 
brown dots. Host: Gadus morrhua. 
P. subfasciata.—Transverse bands across the body. Suckers circular, 
and the posterior broader than the abdomen and twice the size of 
the anterior. Host: Gadus merlangus. 
P. gracilis.— Posterior sucker a quarter as broad again as the anterior, 
broader than the abdomen; body irregularly dotted; no bands. 
Host: Trigla gurnardus. 
Now, when we come to consider that the most prominent specific character 
of Calliobdella nodulifera is that the posterior sucker is broader than the 
abdomen and twice the size of the anterior sucker (though Malm says it is 
not quite), and the next important that it is dotted irregularly with brownish- 
yellow, we can, I think, very easily read these characters to cover what is 
written about the three preceding species, such distinguishing marks as a 
sucker being “as quarter as large again” being of but little use in a spirit- 
preserved specimen, where only a unit multiple such as twice as large, or 
four times as large, is the least that can be appreciated. In none of these 
