LIVING BRACHIOPODA. 343 



occur iii all the Lingulidae but owiug to their small size have escaped notice hi preserved 

 specimens. The oesophagus is cylindrical, slightly bulging in a contracted state, and has 

 broad longitudinal markings due to folds within. It enters the stomach as a straight 

 tube (47: 5, ti). The stomach is quite different in shape from that of Glottidia, being 

 acutely triangular, the base of the triangle being posterior and the sides curving slightly 

 inward. When the oesophagus is retracted, the anterior portion of the stomach projects 

 on each side like two horns (47: 5). The surface of the stomach is thrown into vermi- 

 form folds and in life these folds are continually in motion, expanding and contracting 

 (48: 5). The intestinal canal, as in Glottidia, is strongly ciliated. 



In Glottidia the rectum perforates the lateral coelomic wall obliquely and shows a 

 distinct projection outside, the anus being marked by six flat tubercles (50: 10). In 

 L. Icpidula the rectum enters the coelomic wall in precisely the same manner. The anus 

 is bordered by six folds or blunt scallops like the petals of a flower, the notches between 

 these folds continuing within the rectum as lines, due to longitudinal folds (50: 11). 

 This is its appearance in life, and the parts vary in their appearance as shown in 50 : 12. 

 The anus in Glottidia was drawn from an alcoholic specimen. In both Glottidia and 

 L. Iqj'xltila it will be observed that there are six tubercles or folds, and in life the anus of 

 Glottidia would probably present the same petal-like appearance as seen in L. lepidula. 

 The faeces appear as oval pellets. 



In D. lamellosa the head is very prominent and is probably very mobile ; the mouth, - 

 as in the lAngulidae, is turned abruptly downward and the oesophagus runs directly 

 upward reaching nearly to the dorsal shell, where the parts are held in place by the dorsal 

 mesentery (49: 3). The stomach shows but slight enlargement; the intestine descends 

 posteriorly toward the ventral shell and is cylindrical throughout. The anus is a mere 

 perforation in the coelomic wall and is marked by a few radiating wrinkles (50: 13) . In 

 the early stages the stomach appears as a large globular cavity ; a slight constriction 

 occurs as it enters the intestine, which turns to the right and which has a slight dilatation 

 before it enters the narrow rectum (50:14,15; 61:7,10). In D. stella, the head is 

 dark brown and quite prominent. In the early stages, the stomach is large and globular, 

 nearly filling the coelomic cavity; a short intestine follows, turned abruptly to the right. 

 The animal is represented in 61 : '2 as seen from the ventral surface. 



In T. septentrionalis, the wide expanded lips of the mouth show great mobility in 

 the young; the lips are thrown into one or more folds and are in continual motion. The 

 outer layer of the intestine is composed of longitudinal muscular fibres, and when cut 

 through, the muscular layer contracts, drawing the cut edges back as shown in 50: 16. 

 The faeces in spiral fusiform shape, are ejected through the mouth. 



In H. psittaceci, the alimentary tract, when divested of its attachments, assumes its 



