ECHINOTHURIDiE. 85 



gested in the "Blake" and "Challenger" Reports. There is not one, 

 according to him, of any value, because they are not based upon the 

 pedicellariae. 



Dr. Mortensen thinks I am wholly mistaken in suggesting any affinity 

 between A. pellucidum and A.coriaceum and A. tessellalum, because he has sug- 

 gested a new genus, Hoplosoma, for A. pellucidum, based entirely upon the 

 structure of the pedicellaria 1 (PI. XIII, figs. 20, 24, 25); they are certainly 

 very peculiar, but may be embryonic conditions of unknown pedicellarire 

 similar to those he figures for Ph. placenta (PI. XII, figs. 15, 24, 30). As for 

 his remarks on Phormosoma ienue? I would sutro-est to Dr. Mortensen that 

 the Report on the " Challenger " Echini was issued in 1881, and that his 

 Memoir was published in 1903 ; he can hardly expect genera proposed 

 in 1903 to have received any recognition in 1881. 



I have nothing to say regarding Dr. Mortensen's sneers at descriptions 

 of pedicellariae 2 because they do not lit with his classification. I have 

 no doubt that, in the mass of material collected by the "Challenger" which 

 passed through my hands 1 must have failed to distinguish all the species. 

 I was frequently in doubt as to the identification of certain specimens. 

 That doubt was usually indicated on the labels accompanying them, but 

 Dr. Mortensen 3 has no words to express his horror at such a, proceeding. 

 It is therefore somewhat surprising that he should, without any exami- 

 nation of the pedicellariae, refer P/iormosoma hoplacantha to the genus 

 Hygrosoma which he has established for Ph. Petersu, described in the 

 Preliminary Report of the "Blake" Echini, and which I subsequently 

 considered to be Ph. uranus Wyv. Thorn, in the final Report. 



Dr. Mortensen holds me responsible for the identification of specimens 

 of Ph. uranus anil Ph. Petersu sent by the Smithsonian (National Museum) 

 to the Copenhagen Museum and to Professor Koehler. I must repeat 

 again that I know nothing of the specimens collected by the "Albatross" 

 in the Atlantic after the publication of the " Challenger " Echini. As the 

 Report on the "Challenger" Echini was published in 1881, and the 

 "Albatross" was not launched until 1883, I cannot have had in 1881 

 any opinion regarding the identity or difference between the specimens 

 of Ph. uranus and Ph. Petersii on which he establishes the genus Hygrosoma. 

 There are no indications in the figures of the pedicellaria? of Ph. placenta 



i "Ingulf" Echinoidea, p. 55. 



2 Loc. oit. p. 57. 3 Loc. cit. p. 57. 



