LIVING BRACHIOPODA. 355 



In the peduncle of Glottidia, the inner tubular cavity shows a continuous circulation of 

 fluid, the corpuscles coursing down the centre to the extreme end and returning on either 

 side, probably in the deep folds which are shown in a transverse section of this part. In 

 a peduncle in the last stages of dissolution, the blood was seen circulating as usual, though 

 the peduncle had been for two days separated from a body black with decay. Here again 

 is a circulation of the blood induced solely by ciliary action and not by any propellent 

 organ. 



In L. anatina, the shell was too opaque to observe the circulation of blood in the 

 pallium, though the pallial sinuses and lacunae of this species have often been figured 

 and described. The anterior border of the palliiim is light brown and this color extends 

 around the entire margin ; just within this brown border, the pallium becomes the purest 

 white and toward the centre a greenish tinge is seen. The pattern of brown pigmen- 

 tation of the pallium is figured in 52 : 10. From the above observations on the circu- 

 lation of the blood in the Lingulidae, it is certain that a propellent organ or heart is 

 wanting in these animals. 



In D. lamellosa, the body cavity is somewhat quadrangular in shape, occupjdng the 

 posterior half of the boundaries made by the orbicular shell. It is rounded behind, 

 dilating somewhat toward the anterior portion on a line with the stomachal glands, then 

 narrowing in line with the anterior occlusors, which stand oblique to the median line, and 

 terminating in front with a median depression just behind the head which projects 

 considerably (49: l). From the shoulder on each side of this anterior depression spring 

 the anterior sinuses and on the side where the coelomic wall slightly projects, spring the 

 lateral sinuses. The anterior sinus follows very near the median hue and terminates in 

 two slender branches. A short distance from its origin a branch turns abruptly backward 

 and recurves upon itself; this sinus sends a number of branches toward the anterior 

 portion of the pallium. The lateral sinus has two branches, one turning abruptly 

 forward and the other abruptly backward. These branches supply three fourths of the 

 pallial area with its lacunae ; they divide and subdivide into minute ramifications which 

 cover every portion of the pallium. The palhum is remarkably rich in these minute 

 ramifying lacunae, and, so far as these were traced, the central cihated ridge was observed 

 in all of them. Blochmann, in his drawings, shows a narrow dark center to these ciUary 

 ridges and in every case represents a slight interspace where they branch off: from the 

 central one, and this follows down to the minute branches. In D. stella the pallium is 

 bordered with dark brown and at the base of the setigerous follicles a distinct red line is 

 observed. At the base of the setae, which are deeply inserted, a sinus runs parallel to 

 the pallial border. This sinus has slight swellings at uniform short intervals, and within 

 each swelling was observed an elongated nucleus which I supposed to be a cihary fold. 

 The radiating pallial sinuses were not observed (44 : 4, 5) . 



