Hirudinea of the Canadian Arctic Expedition, 1913-18. 
By J. Percy Moorr 
University of Pennsylvania. 
The Canadian Arctic Expedition, from 1913 to 1916, yielded a very few 
leeches. These are contained in four bottles sent to me along with a few bottles 
of planarians by Mr. Frits Johansen. There are but two species, already well 
known from the seas of northern Europe but as they have not been recorded 
previously from American waters it seems worth while to publish a notice of 
the extension of their known geographical range. Both belong to the family 
Ichthyobdellide. 
Family ICHTHYOBDELLID-. 
Abranchus scorpii Malm. 
This species, with which A. brunneus Johansson is probably identical, is 
represented by nineteen specimens varying from 14 mm. to 40 mm. long and 
from -8 mm. to 2-7 mm. in maximum diameter. All of the specimens are nearly 
terete or only very slightly flattened, the young ones most so. The greatest 
diameter is shortly behind the middie from which it tapers both ways but 
unequally. The anterior end is more slender and more gradually tapered but 
there is no distinct division into two regions. In the better preserved specimens 
both oral and caudal suckers are large, thin and widely expanded, the oral 
relatively less so on the larger examples. 
On none of the specimens is the annulation strongly marked, the somites 
being dominantly triannulate with the secondary annuli more or less well 
differentiated. Thus in the widest part of the posterior region the neural or 
middle primary annulus is enlarged and clearly subdivided into secondary 
annuli which, however, are smaller than the entire first and third primary 
annuli so that we have the formula (b! + b?) <b? + b4> (b'+ 6°). In the an- 
terior region development of annuli has gone less far, being recognizable only 
in the neural annuli. The formula is, therefore, A! <(b3+ b‘)>A?. The 
sensille and larger non-segmental cutaneous sense organs are developed on 
annulus 6? and a few smaller ones on 6!, b? and 6°. 
The fresh colour as described in the collector’s notes is ‘‘a dark purple- 
brown main-color; strongest red in shape of segmental bands. The two ter- 
minal suctorial discs pale inside with the brown muscles shining through. Eyes 
black.”” The preserved specimens differ considerably chiefly as a result of 
size and fading. Those from station 42™ are most deeply pigmented, being 
of a dark reddish brown above, paler below. The margins of both discs, two 
transverse bands on the oral disc and radiating lines and marginal spots on 
the caudal disc, several transverse bands on the body, and the region about 
the anus also paler. Those from station 49% are pale reddish brown above 
with whitish transverse bands especially conspicuous laterally on the first 
annulus (A!) of each somite. All of the parts indicated as pale reddish on the 
specimens from 42" are on these whitish. Small individuals are nearly 
colourless. The sensille and non-segmental sense-organs are clear white and 
very. conspicuous on dark specimens. The three pairs of eyes are black and 
arranged as figured by Johansson. The caudal eye-spots also are black, small 
and arranged in a circle at the central ends of the pale marginal spots. . 
Following is a list of the specimens with labels and collector’s notes quoted 
in full: 
