4 Spong. 
SP0NGI2E. 
49. [Yosmaer, G. C. J.] The Sponges of the ( Wm, Barents’ Expe¬ 
dition, 1880 and 1881. Bijdr. Dierk. xii., 47 pp., 5 pis. 
50. Wierzejski, A. O Rozwoju Pakow (Gemmuloi) gabek slodkowo 1- 
nych, europejskich, tudziez o gat. Spongilla fragilis , Leidy ( S. 
sibirica, Dyb.). Rozpraw i Spraw. wydz. matem.-przyr. Ak. Umiej. 
1884. 
51. Wrzesniowski, A. Stanowisko gabek w systematycs zwierat wedlug 
Marschala (Position of the Sponges in the Animal Kingdom, accord¬ 
ing to Marshall). Wszechswiat, 1885, iv. pp. 563 & 564. 
52. Zahalka, C. Ueber Isoraphinia texta , Roem., sp., und Scytalia per- 
tusa , Reuss., sp., aus der Umgebung von Raudnitz a. E. in Bohmen. 
SB. Ak. Wien, xcii. pp. 647-652, & pis. 
Anatomy and Histology. 
Lendenfeld (11, 13, 14, 16, 18, 19) describes nervous elements from 
several species of Ccilcispongia and Ceratosa. The sensitive cells are 
fusiform, with a central oval nucleus ; they occur singly, or in clusters or 
rings, in the vicinity of incurrent apertures, lying at right angles to the 
outer epithelium, through which the distal end of each protrudes as a 
fine hair-like process or palpocil; the proximal end extends inwards as a 
long thread, which sometimes ramifies, and can occasionally be traced 
into connection with another cell which resembles a multipolar ganglion 
cell. These apparent ganglionic cells are sometimes situated between 
the sensitive cells and muscular sphincters. 
In Bell’s “ Comparative Anatomy and Physiology ” [London : 1885], 
p. 431, there is an account (and figure) of C. Stewart’s observations on 
the sensitive elements of Grantia rciphanus. These, which form a ring 
about the entrance to the incurrent canals, resemble stellate mesodermal 
cells, with one process always directed at right angles to the outer 
epithelium, which is raised immediately over it (as if to receive it) into a 
sharply pointed conical eminence. 
Polejaeff (28) gives a full account of the anatomy aud histology of 
the Ceratosa. 
Lendenfeld (12-20) gives a full account of the anatomy and histo¬ 
logy of the Calcarea , some Myxospongia, and a large number of Ceratosa. 
Amongst the Calcarea , a new genus, Homoderma , is described, combining 
the anatomy of a Sycon wdth the histology of an Ascon ; amongst the 
Myxospongice a new genus, Bajalus, with Sycon-like flagellated chambers, 
is described. 
Sollas (40 & 41) shews that Zittel in both his earlier and later views 
is mistaken as to the structure of the skeleton in the Anomocladina. It 
consists of sclerites having a massive centrum from which a variable 
number of rod-like rays proceed. These terminate in expanded ends, 
which embrace the centres of neighbouring sclerites, and so produce a 
firm network. 
Sollas (42) finds the refractive index of siliceous spicules for light to 
be P449, nearly the same as that of opal (P446). Calcareous spicules 
