1873.] B20 [Morze, 
the body is in most cases distinctly divided into a thoracic portion, 
and an abdominal, or caudal portion. In Pectinaria the caudal por- 
tion is separated from the body by a deep constric- 
tion, and is apodous. In Serpula, Protula, and Ly- 
silla, the separation of the body into two regions is 
strongly marked. In Sabellaria alveolata, the caudal 
portion is very long, cylindrical, and apodous. :.) 
In the Brachiopods, the body is also distinctly di- Ale 
vided into a thoracic and caudal portion. The cau- 
dal portion varying greatly in function and charac- 
ter, in different groups. In some, this portion is very 
short, and firmly fixed to some point of support. In Rhynchonella 
and Terebratulina it is capable of sustaining the body, and of twirl- 
ing it round in various directions, or more correctly the peduncle 
appears to be firm and elastic, and the body is capable, by certain 
muscles, of twirling round upon it. In other Brachiopods, as in 
Discina, the peduncle, or caudal portion, has its special set of mus- 
cles, attached to the outside of the ventral plate, and its cavity is 
in direct communication with the perivisceral cavity by an azygos 
opening. 
In Lingula pyramidata (and I presume the other forms of Lingula 
will present no essential difference) the peduncle is nine times as 
long as the thorax, free, active in its 
vermian contortions, and possessing the Fig. 6. 
power of fabricating a sand tube. The 
thorax also possesses this power. (See 
figures 1 to 7 in Plate I.) Not only 
is the body often enveloped in a sand 
case, but this species of Lingula has 
the power of covering the bottom of 
any vessel in which it may be confined 
with a sinuous sand tube, precisely sim- 
ilar to the tubes made by Terebella, 
and allied forms under like circumstan- ity py ramidiatshowink an: 
ces. (See Fig. 7, Plate I.) Though Doane OS ae 
the peduncle of Lingula is capable of 
varied and rapid movements, is partially annulated, shows a constant 
circulation of the perivisceral fluid within, is possessed of mucous 
pores, yet no trace of sete are seen upon its walls, and this is in 
Fig. 5. 
Young Rotifer. 
