164 Herbert L. Hawkins — Studies on the Echinoidea, etc. 



There can be no doubt that the figures of Galerites umbrella in the 

 Encycl. method, (pi. cxlii, figs. 7, 8) represent a species of Clypeus, 

 presumably C. sinuatus, Leske. The descriptions given by Lamarck, 

 Deslongchamps, and de Blainville all agree more closely with the 

 generic characters of a Clypeus than of a Pygaster. Agassiz (1839) 

 hesitated to include C. sinuatus, Leske, in his list of synonyms of 

 P. umbrella, although he inserts the Nucleolites umbrella of Desmoulins, 

 which included Leske's species. Desor (1842), following on and 

 amplifying the descriptions of Agassiz (probably with his collabora- 

 tion), definitely placed Clypeus sinuatus among the synonyms of 

 P. umbrella, and, to complete his identification, inserted a reference 

 to the description and figure given by Klein (1734) as C. plotii. In 

 1847 ( Cat. Pais.) both authors jointly recognized the error of 

 including Clypeus sinuatus in the genus Pygaster, and deleted all the 

 previous synonyms of P. umbrella except the reference to Lamarck. 

 They gave to the original P. umbrella the new name of P. dilatatus, 

 and, to add to the confusion, briefly diagnosed a new species under 

 the old name ; surely a most disastrous way of rectifying a mistake ! 

 With this complication, however, we are not immediately concerned. 

 The question of the relation between the names semisulcatus and 

 umbrella (supposing them to refer to the same species) turns on the 

 description of Galerites umbrella by Lamarck. The use of the generic 

 term Galerites affords no guidance, for Lamarck applied it to many 

 forms which cannot be classed as Holectypoida. He gives a reference 

 to Clypeus sinuatus, Leske, and to the figure in the JEncyclopedie 

 (Lamarck, An. s. vert., iii, p. 23), and describes his Galerites umbrella 

 as " sulcis ambulacrorum angustis biporosis substriatis". As Salter 

 remarked (Mem. Geol. Surv., Dec. V, 1856), the last word seems to 

 imply a petaloid or subpetaloid ambulacral structure that is in- 

 compatible with the characters of a Pygaster. There seems, therefore, 

 little doubt that Lamarck's species was a Clypeus or a Nucleolites, 

 and was thus in no way to be identified with the Pygaster umbrella 

 of Agassiz in 1839, nor with the later species given that name 

 in 1847. 



Since all the references given by Agassiz in 1839 for P. umbrella 

 seem to have no real connection with that species, it follows that the 

 name P. umbrella, Agassiz, 1839 {excl. syn.), can be applied only to 

 the form figured by him — known at that time by a unique and partly 

 decorticated specimen, from the " Portlandien du Jura Soleurois". 

 The name itself, denuded of its list of synonyms, is valid enough, but 

 it dates back no further than 1839. Hence, if Clypeus semisulcatus, 

 Phill., and Pygaster umbrella, Agass., are synonymous, the former 

 name has ten years priority, and can in any case be maintained. 



Morris {Cat. Brit. Foss., 1843), and later Salter (loc. cit.), 

 recognized the true nature of Lamarck's Galerites umbrella, and 

 followed Desor in his identification of the two species, but naturally 

 regarded P. umbrella as a synonym of P. semisulcatus. Unfortunately 

 Salter's P. semisulcatus was quite a different species from Phillips' 

 original one, so that the way to further confusion was opened by his 

 otherwise logical action. 



It seems doubtful whether any reliable specific criteria can be 



