OF THE EOTATOEIA. 423 



them glands, and doubts likewise the secretory character of the similar but 

 larger bodies seen in the neighbourhood of the oesophagus." 



The glands are usually transparent, or have only a slight milky opacity ; 

 they contain fine nucleated granules and molecules, and in some examples, 

 e. g. Polyarthra (XXXVIII. 39) and Pterodina, a few small oil vesicles. 

 Externally they are invested by a transparent homogeneous membrane, to 

 which, in Alhertia, Dujardin assigned an active contractility ; but this is very 

 doubtful. '' They are," says the French naturahst, " stalled sacs, placed at 

 the commencement of the intestine, susceptible of contraction, pouring out 

 their secretion into the intestine, from which they again fill themselves, and 

 undergo dilatation : in this example at least, these appendages must be con- 

 sidered caeca rather than glands." '' Sometimes," Leydig observes, " the 

 elements of the contained granular mass have an elongated figure, as in No- 

 tms; and then the contents of the glands assume a striated appearance." 

 This account recalls that given by Mr. Williamson of a glandular structure 

 he supposes may possibly represent a spermatic gland ; but of this hereafter. 

 Cohn believes he detected the exudation of a blackish granular fluid fi'om 

 these glands in Hydatina senta, and its entrance within the stomach by a 

 definite apertiu-e. . 



The granular vesicles of the glands were termed " vacuoles " by Dujardin, 

 and have been represented by Ehrenberg in many figures, e. g. of Euchlanis 

 macrura, E. dilatata, Megcdotrocha, and Lacimdaria ; they have also been 

 spoken of by him as " glands, vesicular within." Moreover the shai-ply- 

 defined clear vesicles he has represented in Theorus (XXXIY. 427-429) and 

 Pterodina, and termed " eyes," Leydig believes to be notliing else than fat- 

 vesicles of the gastric glands. Mr. Dahymple has accurately figured these 

 glands in his so-called Notommata {AsplancJma) Anglica (XXXVI. 9 g). 



The function and homologies of these gastric glands are doubtful. Ehren- 

 berg's first notion of them was that they were spermatic ; but he subsequently 

 changed his \'iews, and called them '' pancreatic." ^' For what reason," says 

 Prof. Rymer Jones, " Ehrenberg has given the name of pancreas to these se- 

 creting ca^ca, it is difficult to conjecture, since the first rudiments of a pan- 

 creas are only met mth in animals far higher in the scale of animal existence ; 

 ever}^ analogy, indeed, would lead us to denominate these caeca the fii'st ru- 

 diments of a liver, by far the most important and universal of the glandular 

 organs subservient to digestion, and in a variety of creatiu-es presenting an 

 equal simplicity of structure." 



However unsupported the notion of the pancreatic or saKvary nature of 

 these glands may be, it has met with several advocates, who have in all pro- 

 bability assigned to them this function rather from the want on their part of 

 any definite opinion of their character than for any other reason. Thus Dal- 

 rjTuple alludes to them as salivary glands ; and Perty affirms of two filiform 

 vesscl-hke appendices of the stomach (?) in Enteroplea, that they are repre- 

 sentatives of the pancreas or of salivary glands. Siebold adopted a similar 

 hypothesis ; but Leydig, on the contrary, regards them, in a morphological 

 pomt of view, not as pancreatic glands, but as the analogues of those pro- 

 cesses often seen on the stomach of ArthroiJoda ; he would therefore desig- 

 nate them generally gastric glands, — a view with which we are disposed to 

 coincide. The small glandular appendages on the dorsal sm^face of the sto- 

 machs of starfish, suggest themselves as of the same natin-e as the appendages 

 under consideration. 



A yellowish clear body is situated on each side of the pharynx, imme- 

 diately in front of the maxillary bulb, in Lacimdaria, Tubicolaria, Melicerta, 

 and Brachionv.s (XXXIX. 16), and rather within the substance of the bulb 



