235 



\ 

 runs counter to the opinion as to the sole functions of the organ ex- 

 pressed by Mr. Bourne in his paper); pointed out that (as might have 

 been expected if the organ serves as the efferent duct of the repro- 

 ductive organs), the orifice is wider and the papilla on which it opens 

 shorter in females than in males; described in the females of species 

 in which the eggs are hatched under the elytra the arrangement of 

 long cilia on the parapodia by which the ova might be carried upwards 

 to this position, and pointed out this absence of these cilia in forms in 

 which the eggs are not received under the elytra. These were all facts 

 which are of some importance in determining the functions of the or- 

 gans in question; yet, according to Mr. Bourne they amount to no 

 more than the expression of the »pious opinion« that the openings are 

 the openings of segmental organs. 



But I have something more against Mr. Bourne which, as it is 

 concerned with the acceptance as an ascertained fact of which is simply 

 a new form of an old error, it is necessary I should allude to here. Mr. 

 Bourne's chief claim to originality of discovery in connection with 

 this subject, as contrasted with my expression of pious opinion, is his 

 discovery of the character of the internal openings of the nephridia, 

 and he gives a figure of the entire organ which he states is a diagram 

 compiled from observations on specimens under the compensorium, 

 teased specimens and sections : in this he represents the organ as open- 

 ing into the perivisceral cavity by a wide, funnel-like, ciliated mouth. 



Now Mr. Bourne has here fallen into an error which, in other 

 forms, has been committed before, and which is perhaps excusable 

 enough, but it would be a great pity should the error come to be re- 

 accepted as an ascertained fact of science as might very well happen. 

 -x'X segmental organ of Polynoë, as of Apiwodita •, does not end in any 

 such dilated internal opening as Mr. Bourne describes, and the error 

 into which he has fallen has sprung from a neglect to study carefully the 

 whole structure of the animal. The arrangement of the intestinal caeca 

 in particular he does not seem to have understood ; he alludes to the 

 cilia<;ed funnels described by Ehlers, and merely adds that Grube 

 was unable to trace the connection between these and the external 

 openings. Now I shewed in my paper that these ciliated funnels, as 

 can be seen with the utmost distinctness in transparent forms, such as 

 Antino'é praeclara, are the openings of the narrow ciliated necks of the 

 caeca into the intestine. When the caeca are drawn upon they are 

 readily torn away and separated from the intestine, leaving on the one 



' For an accurate drawing of the general form of the organ in the latter genus 

 see Selenka, »Das Gefäßsystem der Aphroâita aculeatm. Nied. Arch. Zool. Bd. II. 

 Taf. III. 



