REPORT ON THE ASTEROIDEA. xix 



In November and December 1840, and consequently only a few months later than 

 Midler and Troscbel's preliminary paper above referred to, Gray 1 published a synopsis of 

 the genera and species of starfish. He divided the Asteroidea into two unnamed sections, 

 one characterised by havinsr four rows of ambulacral tube-feet, the other having two 

 rows. The first section contained one family, named " Asteriadae ; " the second section 

 three families, named Astropectinidee, Pentacerotidae, and Asterinidae. These four families 

 comprised forty-five genera and nine subgenera, which were briefly denned by structural 

 characters. This classification was republished as a separate work 2 in 18G6, with a few 

 alterations and eight additional genera which had been described in the interim. 



In 1869 Perrier 3 published a valuable memoir on the pedicellariae of Asterids and 

 Echinids. 



In 1875 Perrier 4 pointed out that the characters upon which the sectional divisions 

 or families made by Mtiller and Troschel and by Gray were based were insufficient and 

 unsatisfactory. He insisted upon the importance of the pedicellariaa as a classificatory 

 factor, and he divided the group into two unnamed divisions by means of the character 

 of the pedicellariae and of the disposition of the ambulacral tube-feet. The first division 

 was characterised by the presence of pedunculate forficiform or forcipiform pedicellariae, 

 and a usually quadriserial arrangement of the ambulacral tube-feet ; the second division 

 by sessile, pincer-formed, or valvate pedicellariae, and a usually biserial arrangement of 

 the ambulacral tube-feet. The first division contained only one family, the "Asteriadae;" 

 the second division sis families, the Echinasteridaa, the " Linckiadaj," the Goniasteridae, 

 the Asterinida3, the Astropectinidae, and the Pterasteridae. These seven families embraced 

 forty-five genera (forty-two recognised in the text), a number of Gray's genera being 

 absorbed or altered. Both families and genera were characterised by the structure of the 

 skeleton. This work contains a careful revision of the species contained in the Museum 

 d'Histoire Naturelle of Paris, and supplemented by those in the British Museum. 



In 1878 Viguier 5 published an elaborate investigation on the Asterid skeleton, and 

 propounded his discovery that in the mouth-ring of some starfishes the ambulacral plates 

 were predominant, whereas in others the adambulacral plates were predominant. He 

 also showed that a great range of variation occurred in the form of a plate which he called 

 the " odontophore " (the basal interbrachial plate), as well as in the character of the 

 mouth-plates, which he called teeth. 



1 A Synopsis of the Genera and Species of the Class Hypostoma (Asterias, Linnaeus), Ann. and Mug. Nat. 

 Hist, 1840, vol. vi. p. 175. 



2 Synopsis of the Species of Starfish in the British Museum, London, 1866. 



3 Recherches sur les PMicellaires et les Ambulacres des Asteries et des Oursins, Ann. Sci. Nat., 5e Sene, 

 t. xii. 1869, p. 197. 



4 Revision de la Collection de Stellerides du Museum d'Histoire Naturelle de Paris {Archives de Zool. 

 exper., t. iv. 1875, pp. 265-450 ; t. v. 1876, pp. 1-104, 209-304). 



5 Anatomie compared du Squelette des Stellerides (Archives de Zool. exper., t. vii. 1878, pp. 33-250, pis. 

 v.-xvi.) 



