Spong. 1 
SPONGIiE. 
BY 
E. A. Minchin, T3.A. 
INTRODUCTION. 
The number of titles this year is G8, among which are included a certain 
number belonging to 1890, which the Recorder for that year was unable 
to obtain. 
A large proportion of the morphological works of 1891 deal with the 
Calcarea. Their anatomy aud histology are discussed by Dendy (1, 4), 
von Lendeneeld (1), and Bidder ; while Rauff (1) describes in detail 
the structure and mode of growth of a most interesting new group of 
fossil Sycons, which he terms Polysteganinai. Keller has many remarks 
on the anatomy of Oligoceralina and Tetractinellida, and also an inte- 
resting and important theory on the origin of spongin and the mechanical 
adaptation of the sponge skeleton to external conditions of life. Dendy 
(2) describes the flagellated chambers of Ilalicliondria panicea , in which 
he asserts, against von Lendenfeld [see Zool. Rec. 1890], the presence of 
Sollas’s membrane, which he has found also in various Calcarea. [See 
also Dendy (1, 4).] 
In embryology, Delag e has some very extraordinary statements con- 
cerning the development of Spongilla, which will certainly need abundant 
confirmation before they can be accepted, the more so as the author gives 
us no clue as to the methods employed by him in arriving at such novel 
rbsults. Wilson describes what he terms the gemmule development of 
some species of Monaxonida ; but it would appear probable, even from 
his own figures, that what he has mistaken for gemmule formation is in 
reality the segmentation of the ovum. 
Dendy (4) gives a classification of Ilomocccla which has very little in 
common with that given by von Lendenfeld (1,3) in his classification 
of Calcarea in general. Keller (1) introduces some changes in the 
classification of Monaxonida. Important systematic works are : for recent 
forms, Dendy (4), Keller (1), von Lendenfeld (1), Topsent, Weber, 
