NO. 3652 ISOPODA AND TANAIDACEA—MILLER 47 
Family EXcORALLANIDAE 
Excorallana subtilis (Hansen) Richardson 
Figure 4 
Locauity.—Florida: Tampa Bay (Station 50). 
Remarxks.—Hansen (cited by Richardson, 1905b) records Excoral- 
lana subtilis from St. Thomas, West Indies. She also hesitatingly refers 
to this species two male specimens from Florida (specific locality not 
given) in the collection of the U.S. National Museum. These fit the 
description except for the lack of the two large tubercles at the base 
of the terminal abdominal segment. The specimen from Florida, an 
ovigerous female, agrees nicely with the description except that the 
two tubercles on the pleotelson are not as large as those figured by 
Richardson. Probably the presence and size of these tubercles are 
variable characteristics. 
Suborder VALVIFERA 
This suborder (containing some 600 species; Waterman and Chace, 
1960) is represented in the collection by eight species, all in one family, 
taken from 48 buoys. 
Of the two valviferan families known in North America, the Astacil- 
lidae (=Arcturidae) and the Idoteidae, only the latter is represented 
in the buoy collections. This family occurs mainly in the temperate 
zone and boreal zones, whereas astacillids are characteristic of still 
colder waters. Both families, however, have representatives in tropical 
or subtropical waters and the ranges of some extend into warm waters. 
Valviferans in general, however, are represented poorly in the tropics. 
In the buoy collections only one of eight idoteid species (Jdotea 
resecata) was found south of 35° north latitude. 
Family IDOTEIDAE 
Subfamily IDOTEINAE 
Only two idoteid genera were found, both in the subfamily Idoteinae 
to which most idoteids belong: Jdotea, with six species, and Synidotea, 
with two. The six species of Jdotea were divided evenly between the 
Atlantic and the Pacific coasts. They probably are ecological equiva- 
lents. Both species of Synidotea were found on buoys along the Pacific 
coast. Synidotea is predominantly a North Pacific genus with only two 
circumarctic or circumboreal species known from the North Atlantic. 
As previously mentioned, some idoteids, as well as sphaeromatids, 
are good swimmers, which accounts for their relatively greater fre- 
quency on buoys than the more sedentary isopods. Two species, 
Idotea balthica (=marina) and I. metallica, have been reported from 
widely separated localities in both northern and southern hemispheres. 
281-333—68——2 
