338 THE SPONGIDA OR PORIFERA. 



these being formed from the ordinary development and segmenta- 

 tion of ova. In 1872, Haeckel published his Monograph of the 

 CalcispongicE, in which he still further insisted on the near con- 

 nection of the Sponges with the Corals, declared that he had 

 observed spermatozooids, as well as ova, in several species of the 

 Spongida, and that the ciliated larva or gastrula, from which all 

 Sponges developed (and which occurs throughout the animal scale 

 from the Sponges up to the Vertebrates, " as represented by 

 Amphioxus "), was an embryonic representation of an ancient 

 and primitive animal form termed " Gastrcea,'" from which the 

 various animal types have descended. 



The eminent position of Haeckel, and the ingenuity, the force, 

 and brilliancy of his writings and arguments, took — so to speak — 

 the biological world by storm ; and his teaching became widely 

 accepted, his opinions quoted, and his illustrations copied by the 

 authors of many subsequent standard works and text books, All 

 this, however, caused renewed and increased attention to be 

 directed to the Spongida, which, in consequence, have been most 

 perseveringly studied by numerous biologists, with the purpose of 

 verifying or refuting the views emphasised by Haeckel. Indeed, 

 so much has been written on the subject, that we are reminded of 

 the dictum laid down frequently and emphatically by the eminent 

 surgeon — the late Mr. Richard Quain : — " When you find that a 

 great deal has been written on any subject, you may feel quite 

 sure that very little is known about it ! " This may seem to many 

 a hard saying, yet it is not inapplicable to the present case. There 

 is still great difference of opinion as regards the true position of 

 the Sponges in the animal scale. "English Biologists," the writers 

 are informed, " as a rule, prefer to place them in a group by them- 

 selves — the PORIFERA ; while continental men — Haeckel and 

 Lang among them — place them under the Ccelenterata." Others 

 there are again, who still consider the true position of the Sponges 

 to be wdth the Protozoa. Saville Kent, for example, in his volu- 

 minous and learned " Manual of the Infusoria," 1881, argues with 

 great force and ability that the Spo/igida are very closely connected 

 with the flagellate collared Infusoria; and in the system of classifi- 

 cation adopted by him, the independent flagellate collared monads 

 form Section L, and the Sponges Section II., of his Order, Choa?io- 

 Flagellata. 



