Report of the State GEOLOGIST. 



509 



which is given off a number of mesenteric bands connecting with 

 the walls of the perivisceral chamber. The stomach is usually 

 enveloped by an ample Iwer of brownish or greenish line Lying 



Fio. 128.— The alimentary and muscular system of Rhynchonella (HemithyrW) psittacea. 

 (Huxley), a, mouth; b, oesophagus; c, stomach and liver: e, imperforate rectum; n, pyriform 

 vesicle; a, pedicle- valve: b, brachial valve. 



for the most part on the dorsal side, in the articulates, and on the 

 ventral side in the inarticulates. 



This glandular organ is composed of a varying number of 

 caecal tubes terminating in follicles or 

 lobules, and discharging into the 

 stomach at different points, usually at 

 the sides. These hepatic canals would 

 seem to serve in some measure a diges- 

 tive function, as they have been found 

 to contain the food of the animal, and, 

 in Rhynchonella, to undergo peristal- 

 tic contractions of the tube-walls. 



In a certain series of linguloid genera 



(LlNGULOPS, LlNGULASMA, TrIMERELLA, 



etc.) there appears to have been a 

 gradual development of a testaceous 

 thickening beneath the insertion of 

 the muscular bauds. This thickening or platform becomes slightly 

 excavated on its anterior margin in Lingulops, more deeply in 



61 



Fig. 129.— A portion^of the liver of 

 Crania, a, hepatic canals; b, canal 

 of the lobules; c, lobules 



(JOUBIN.) 



