818 MR. F. E. BEDDARD ON [NoV, 3, 



Perrier suggests, that they are the homologues of the nephridia 

 belonging to these segments. Similar glands are stated by Perrier 

 to occur in Ferich<ef.a, but in this genus it was not possible to 

 observe the external aperture of the glands. Seeing that the buccal 

 cavity is morphologically external, it is not surprising to find that 

 the same glands may in some cases open directly on to the 

 exterior, and in other cases indirectly by means of the buccal cavity. 

 Similar glands are also found in many of the Limicola ; Vejdovsky 

 in his 'Monographic der Enchytrseiden" records their })resence in 

 several species of EnchytrcBUS, Anachceta, and other genera, compar- 

 ing them with the "glandes a mucosite " of Urochceta. 



Following upon the pharynx is the narrow oesophagus, which 

 presently widens out in the eighth and ninth segments to form the 

 gizzard, an organ that is found in all Earthworms except in Potito- 

 drilus. The structure of the gizzard is in no way remarkable : it is 

 surrounded by a very thick circular muscular coat, outside which is 

 a delicate layer of longitudinal fibres ; a few radiating muscles pass 

 through the circular layer ; it is lined by a tall columnar epithelium 

 which secretes a very thick cuticle. The position of the gizzard, 

 placed as it is along the course of the oesophagus, is the same that 

 has been found to occur in all Intra- and Postclitellian Earthworms ; 

 in Lumbricus alone the gizzard marks the posterior termination of 

 the oesophagus. 



Behind the gizzard the oesophagus is rather wider than it is in 

 front, and becomes extremely vascular ; even in the spirit-preserved 

 specimens which I have dissected, this region of the oesophagus is 

 conspicuous from the abundant presence of blood-vessels, which form 

 two systems : — (1) a superficial plexus, (2) an internal blood -lacuna 

 which surrounds the gut, lying just within the lining epithelium. 



In relation to the oesophagus are developed certain peculiar glands, 

 which appear to correspond to tlie " calciferous glands" oi Lum- 

 bricus. 



In the common Earthworm {Lumbricus) the hinder region of 

 the oesophagus is furnished with three pairs of lateral diverticula, 

 which have been long known as the calciferous glands, or glands 

 of Morren ; of these the anterior pair are the larger. The struc- 

 ture of these glands has been described by Claparcde^ ; in the region 

 where they are found the oeso|)hagus is extremely vascular, and 

 consists of a number of radiately arranged glands or follicles 

 divided by septa of connective tissue enclosing a blood-space. The 

 calciferous gland itself is merely a diverticulum of the oesophagus, 

 and is made up of exactly the same structures, only the follicles are 

 deeper. Claparede states that he has never observed the formation 

 of the calcareous particles secreted by these glands within the gland- 

 substance. 



In the genus UrochcBta, Perrier^ has described three pairs of 

 similar glands, which are of very much larger size than in Lumbricus, 

 but appear to present a more or less similar structure. 



' Loc. cit. p. 29. - Zeitschr. f. wiss. Zool. Ed. xix. 18C9, p. 602. 



^ Arch. d. Zool. Esp. t. iv. 



