58 



distant date, Professor Per ri er lias thought fit to bring a charge 

 against me of so unpleasant a nature that I cannot allow it to pass 

 "without notice. 



It will be seen subsequently from the very nature of this charge, 

 that it relates to matters about which Perrier could have absolutely 

 no personal knowledge whatever. I shall quote in full the statement 

 Avhich he has permitted himself to make, and will only say now that it 

 is utterly untrue, and leave him to extricate himself as best he can from 

 the unpleasant position in which he has placed himself. 



The history of the matter is as follows : 



In a general description of the Pentacrinoid larva of Antedoti 

 published in 1866, Dr. Carpenter 2 said: 



»Beneath the tentacular canal a tubular extension of the perivisceral 

 space passes along the ventral surface of each ray ; and although this appears 

 to form but a single canal, I shall hereafter show that it is very early divided 

 by a horizontal partition extended from the membranous bands that suspend 

 the digestive cavity in the perivisceral space ; and that whilst the canal above 

 the partition communicates with the portion of the perivisceral space which 

 lies immediately round the mouth, the canal beneath the partition is ex- 

 tended from the portion of the perivisceral space which occupies the hollow 

 tf the calyx. The former I shall term the subtentacular, and the latter 

 ohe coeliac canal; their relations will be found very remarkable.« 



Dr. Carpenter thus described the subtentacular canal as sepa- 

 rated from the coeliac canal below it by a horizontal partition. 



The following version of this observation was given by Perrier': 

 «... Comme Müller, dont il s'est évidemment et ajuste raison très-pré- 

 occupé de retrouver les résultats, le docteur Carpenter a vu d'ailleurs, 

 dit-il. le canal tentaculaire divisé verticalement par une cloison trans- 

 versale dans certaines parties de son étendue.« 



Perrier bas here confounded two entirely distinct observations* 

 the one by Müller, the other by Dr. Carpenter. It is well known 

 hat Müller's tentacular canal is the subtentacular canal of later ob- 

 servers, and that it is frequently divided into two parts, right and left, 

 by a vertical partition. But the partition described by Dr. Carpenter 

 was a horizontal one, dividing the subtentacular from the coeliac canal, 

 He spoke of these two canals on another page (702) in the following 



2 Phil. Trans. 1866. p. 728. 



3 Recherehes sur l'Anatomie et la Kégénération des Bras de la Comatula rosa- 

 cea. Arch, de Zool. Exp. et Gén. T. IL 1873. p. 36. 



* I Mould here beg the reader to notice, for reasons which will appear sub- 

 sequently, that this is the first occasion on which I have referred to this error of 

 Perrit I'.s, nearly fourteen years after it was committed. 



