40 On the Morphology of Antedon rosacea. 



body-cavity, I am somewhat surprised at findina^ no reference 

 to them, either in the text or in the figm-es of Messrs. A^ogt 

 and Yung's monograph*. They occupy some of the ' Lacunes 

 periton^ales dans le tissu spongieux vasculaire" (p. 554), and 

 are altogetlier different from the channels within the threads 

 of this tissue that Messrs. Vogt and Yung term " vaisseaux 

 formant de rdseaux," a denomination which I cannot now 

 discuss. Their omission is tlie more surprising as Ludwig 

 has given an excellent description and figure of these inter- 

 visceral vessels in Antedon roso.cea f ; while one of his figures 

 shows their connection with the problematical dorsal organ. I 

 well remember my father directing my attention to these vessels 

 in Antedon rosacea before I ever cut any sections of the disk. 

 He had studied them in his minute dissections with a binocular 

 microscope, a method of research which I have often found 

 extremely useful when applied to moderately thick sections 

 of a large Comatula or Pentacnnus, and I have invariably 

 found these intervisceral vessels in the disk of every Antedon, 

 Acti'nometra, Promachocrinus, or Pentacrinus which I have 

 cut into sections. Their relations to the other poi'tions of the 

 vascular system are fully described in the 'Challenger' report. 

 I am really very sorry to have been obliged to speak so 

 strongl}^ with respect to a work which is associated with the 

 honoured name of Prof. Carl Vogt, and I should not have 

 noticed it at all had it been a mere students' text-book com- 

 piled in the ordinary way ; but the prefatory statement that 

 theTraite "sera composee d'une serie de monographies anato- 

 miques de types, resumant I'organisation animale toute en- 

 tibre," and its publication in two languages so as to bring it 

 within the reach of a larger number of students, necessitate 

 its being judged by a much higher standard than that of the 

 usual 'Lehrbuch.'' In a work of this kind descriptive accuracy 

 is absolutely essential, and it will be evident from what I 

 have said above that, altogether apart from mere clerical 

 errors, Messrs. Vogt and Yung's monograph is often sadly 

 defective in this respect. Some of their statements, e. g. that 

 respecting the division of the arm-nerves in the first radials, 

 could not have been made by any one who had a proper 

 acquaintance with the literature of the subject which was 

 being treated monographically ; while others, sucli as the de- 

 scription of rents in the skeletal tissues as portions of the 

 system of cavities derived from the coelom, are due to a total 

 misapprehension of the characters of their sections. 



* It is possible that the " vaisseaux coupes " which are lettered o in 

 fig. 271 may belong to this system, 

 t Op. cit. p. 323, Taf. xvii". figs. 52, 56 ; Taf. xviii. figs. 57, 59. 



