TITLES. Spong. 7 
[Weltner, W.] (50) Zool. Rec. 1894. Summary, Zool. Ceutralbl. 
ii, pp. 586 & 587. 
Wilson, H. V. (52) Zool. Rec. 1894. Summary, J. R. Micr. Soc. 
1895, p. 320. 
70. Zacharias, O. Forschungsberichte aus der Biologischen Station zu 
Ploen. Berlin : (1894). 
II. BIOLOGY. 
MORPHOLOGY and PHYSIOLOGY. 
a. General (31, 48). 
James (31) gives a short popular account of the life-history of 
Spongos. 
Minchin (48) concludes from his observations on the formation and 
growth of the spicules in Ascetta coriacea that this Sponge and the lower 
forms of Sponges generally, have no “ mesoderm,” but consist of the 
two primary layers only: (1) the dermal layer, which is composed of the 
outer superficial neuromuscular, and the inner connective tissue cells ; 
and (2) the gastral layer, composed of the collar-cells. To the latter 
perhaps also the amoeboid wandering cells belong. In short, what Schulze 
and others name mesoderm, Zwischenschicht, interstitial layer, Minchin 
considers as a part of the dermal layer. 
b. Canal-System (5, 61). 
Bidder (5) met with ciliated chambers only 0 0067-0 0083 mm. wide 
in a Sponge identical with, or at least closely resembling, Acanthella 
stipitata, Carter. 
Topsent (61) says that three different kinds of ciliated chambers 
occur in the Carnosa : (1) eurypyleuses, which open direct without 
special efferent canals into the sides of the wide efferents ( Placina ) ; (2) 
aphodalos, with short and wide special offorents ( DerrAtus , Corticium ) ; 
and (3) dolichodales, with long and slender special efferents ( Ghondrosia , 
Thymosia). Concerning the efferent canals he finds Sollas’s statements 
and also F. E. Schulze’s figures of Chondrosia not in accordance with his 
own sections, and upholds the views previously expressed on the subject 
by the Recorder. The afferent pores aro scattered over the whole surface 
in the OUgosilicina and in Dercitus , but confinod to the upper face in the 
Mlcrosclerophora. He proposes to replace the old term “ subdermal 
cavities ” (“ cavit^s sous-dermiques ”), which he considers defective, by 
two new terms : “ cavit^s preporales ’’ and “ cavites intracorticales.” 
It seems that Topsent designates as “ pore ” not, as the Recorder and 
others, the openings on the external surface of the Sponge, but the 
entrances to the canals of the pulpa in the floor of the subdermal 
cavities or on the border between pulpa and rind. Thus his “ cavitds 
