Notes on Echinoderm Morphology, No. VII. On 

 the Apical System of the Ophiurids. 



By 



P. Herbert Carpenter, M.A., 



Assistant Master at Eton College. 



With Plate I. 



In a previous volume of this Journal ^ I have discussed the 

 bearings of Ludwig's researches into the early development of 

 the skeleton in Starfishes and Ophiurids on his views respecting 

 the homologies of these two types of Stellerids. Further con- 

 sideration of this question, especially with respect to the 

 Ophiurid-skeleton, has led me to results of some interest, which 

 I propose to explain in the following pages. I should wish, 

 however, first of all, in justice to my friend Ludwig, to correct 

 an error which unfortunately found its way into my last paper. 

 He is represented, on p. 385, as still believing the so-called 

 " odontophore " of Asterids to be homologous with the mouth- 

 shields of Ophiurids. This is a view which he expressed in his 

 earlier papers ^ ; and whatever its intrinsic merits, it is alto- 

 gether untenable if the mouth-shields of Ophiurids represent 

 the so-called " genitals " of Asterids, on account of their 

 mutual relationship to the water-pore, as Ludwig has since 



' Vol. xxii, new series, October, 18S3, pp. 371 — 386. 



2 • Morphologiscbe Studien an Ecliinodermen,' Band i, " Zur Kentniss der 

 Gattung Brisiaga," pp. 231, 235. " Beitrage zur Anatomic der Ophiuren," 

 pp. 263, 269, Band ii. " Das Muudskelett der Asterien und Ophiuren," p. 3. 

 The author has unfortunately omitted the word " friiher " on line 6 of this 

 page, which should read "die friiher von mir angenommene Homologie." 

 Compare p. 16. 



VOL. XXIV. NEW SER. A 



