136 BULLETIN OF THE BUREAU OF FISHERIES. 
The Canadian list of Whiteaves records about the same number of isopods (26) as 
have been listed for Woods Hole. Of these, nearly half (12) are common to the two 
lists. A somewhat greater number (30) is comprised in the Plymouth list, of which 
only 5 appear to be common to our local fauna. Twenty-four species have been 
recorded by Herdman for the Irish Sea, while Graeffe lists 51 species, some of which, 
however, are terrestrial. 
The representation of this order in our dredgings is very slight. The figure repre- 
senting the average number of species per dredge haul is only 0.4, while not a single 
species was taken with sufficient frequency to occur at one-fourth or more of the sta- 
tions. The species having the widest occurrence was Idothea phosphorea, which was 
taken at 72 of the regular stations. 
Only four species of this order were dredged by us with any frequency, and one 
of these (Idothea baltica) probably finds its more proper habitat among rockweed and 
eelgrass, whether growing alongshore or floating at the surface. It is thus possible 
that all of the specimens which were dredged by us actually came from floating material 
of this sort. 
One of the other species, Leptochelia savignyt was only taken at 11 stations, and 
these were all inshore stations of the Phalarcpe series. The species is abundant among 
floating weed, upon piles, etc., and probably does not belong to our deeper water fauna. 
The two remaining species (Idothea phosphorea and Erichsonella filiformis) appear 
with considerable frequency in our dredging records. Of these the latter appears to be 
of pretty general distribution, occurring with nearly the same relative frequency in the 
Bay and the Sound, while the former is in a large degree restricted to the Sound, appear- 
ing in the Bay records only from stations near the lower end, in the vicinity of land? 
Isopods dredged by the Survey. 
*Leptochelia savignyi (chart 103). *Idothea phosphorea (chart 105). 
Cirolana concharum. Edotea acuta. 
Chiridotea ceca. Edotea montosa. 
Idothea metallica. *Erichsonella filiformis (chart 106). 
*Idothea baltica (chart 104). Stegophryxus hyptius. 
Of the four commoner species, one (Idothea phosphorea) may be regarded as pre- 
dominantly northern, having a range upon our coast which is stated by Miss Richardson 
as ‘‘coast of New England to Halifax, Nova Scotia, and the Gulf of St. Lawrence.” 
Two of the species may be regarded as predominantly southern, as follows: 
Leptochelia savignyi.......... Provincetown, Mass., to southern New Jersey (England to Senegal). 
Erichsonella filiformis......... Nantucket Sound to Florida and the Bahamas. 
One of the species (Idothea baltica) may be regarded as cosmopolitan, having been 
recorded from points as widely removed as Java and the Baltic Sea. On our coast it 
is said to range ‘‘from Nova Scotia and Gulf of St. Lawrence to North Carolina.” 
@ Miss Richardson gives the bathymetric range of this species as “‘ surface to 119 fathoms.”’ 
> Our 1909 dredgings confirm these.statements as to both species. 
