EHABDITE-CELLS IN CEPnA.LODISCIJS. 259 



2. " All [the gland-' cells '] have fine pigment granules 



scattered throughout their interior, and a great number 

 of them contain the crystalline lenses referred to." 



3. The base of the " eye " is believed to have been " in some 



cases traced into the main nerve of the plume." 



4. "The whole structure here described seems to indicate 



that these organs are rudimentary monostichous compound 

 eyes, which bear a remarkable resemblance, both in 

 appearance and structure, to the ' branchial organs ' 

 found in the sedentary Annelids, such as Potamilla and 



Sabella It seems most reasonable to regard them 



tentatively as primitive eyes, though the presence of 

 compound eyes in the Chordata is rather remarkable." 



First, as regards matters of fact, I find myself ujiable to 

 confirm the statement as to pigment in paragraph 2, the existence 

 of a nucleus as shown in the figure, and also the belief as to the 

 nerve-supply in paragraph 3. Further, fig. 30 in Masterman's 

 paper is, I must confess, quite unlike anything I have seen. In 

 all my sections the wall of the battery is considerably vacuolated, 

 and I have never seen the cells closely opposed as shown in this 

 figure (q/I my fig. 1). 



Second, as to matters of interpretation, passing over the 

 insufiicient nature of the evidence on which Masterman bases so 

 important a statement, the finer structure of the bodies in 

 question as here described must, assuming the accuracy of the 

 description, be held to negative the view which Masterman has 

 stated. 



In his later paper {op. cit. p. 521) Masterman, in referring to 

 the blastogenesis of the plumes and pinnae, says : " The plumes 

 arise throughout in pairs. They first make their appearance as 

 a papilla, which elongates to a finger-shaped process, the distal 

 extremity of which becomes slightly swollen, and then bulbous. 

 The epithelium of this bulbous extremity then becomes modified 

 to form the eyes. The cuticle of certain of the epithelial cells 

 becomes thickened, and soon the thickening protrudes into the 

 cavity of the cell as a lens-like body. Later it is detached from 

 the cuticle and lies i'reely in the protoplasm. Here it becomes 

 rounded off to form the lens." In plate iv. figs. 75, 76, & 77, this 

 process is illustrated, showing the nucleus of the "eye" at first 

 peripheral in position, and afterwards thrust down to the basal 



