BIOLOGY. 
Spong. 13 
(b) Form and Mode of Growth.—General account; Haller 
( 17) pp. 65-68.— Hamacantha implicans, n. sp., “generally spreads over 
the body on which it is growing, grows round it, and embodies it com¬ 
pletely,” p. 105 : yearly rings of growth in Chalinince , p. 5 ; Lundbeck (38). 
(c) Colour.—Significance of colours in deep-sea sponges; Nutting 
( 44).—Colour of Placospongia due to the possession of coloured spicules 
(sterrospires); Vosmaer & Yernhout (66) pp. 3 & 9. 
(iii) Anatomy of the Soft Tissues. Canal-System . 
Anatomy of sponges in general; Haller (17) pp. 72-75. 
Canal-System of Rhabdodermella nuttingi , n. sp.; Urban (64) pp. 271 
& 272. 
Oscula and excurrent system of Walteria leuckarti Ij.; Ijima (23). 
Anatomy of Placospongia rnelobesioides Gray and P. carinata (Bwk.) 
Rdl.: the name “mastichore” proposed for a region bearing clioano- 
c}*tes, as in Leucosolenia , and “ mastichorions ” for “ the localized small 
regions, known as ciliated or flagellated chambers ;” Vosmaer & Vern- 
hout (66) pp. 4-6. 
Dermal membrane, oscula and pores, homologies of, and application of 
the terms, p. 2; structure of the papillae of Eumastia sitiens , pp. 32 & 33 ; 
canal-system of Oceanapia robusta, p. 80 : Lundbeck (38). 
(iv) Skeletal System. 
(a) General Accounts.—H aller (17) pp. 75-77 : Jordan & Heath 
( 24) pp. 26 & 27. 
(b) Material of the Skeleton.—“ The conclusion.that the 
skeleton of Astrosclera is not calcite, is.satisfactorily confirmed. Its 
properties.agree with those of eonchite, but until the indej:)endence of 
conchite and aragonite is more definitely established, the mineral element 
present in Astrosclera may best be regarded as aragonite;” Hutchinson 
(20). 
(c) Morphology, Development and Nomenclature of 
Skeletal Elements.—The stauractins of the Stauractinophora re¬ 
garded as a modification of the hexactine adapted to support the very 
thin body-wall of these sponges; Schrammen (55) p. 8. 
Silica pearls in Hyalonemci masoni , p. 14 : in H. martabanense , p. 23; 
Schulze (56).—Peculiar globules in the gemmule of Tethya ingalli; 
Sollas (58) p. 215. 
Growth of spicules by apposition; Lundbeck (38) pp. 3 & 53.—De¬ 
velopment of the sterrospirse of Placospongia from spinispirse; Vosmaer 
& Vernhout (66) pp. 6-9, pi. iv, figg. 5, 9, 10, 14, 15, pi. v, figg. 1-4. 
“ Paradises,” a peculiar form of Z-shaped spicules (amphidiscs) occurring 
in Hyalonema alcocki, and in ff. investigator is, pp. 25 & 26, pi. vi, figg. 4 a, 
4 b, 11-16: “ codonhexasters ” for hexasters in which the marginal teeth 
form a deep bell, p. 72, pi. xii, figg. 13-15: “drepanocom” for a form of 
hexaster in which the branch-rays are curved like a scythe, p. 73, pi. xii, 
figg. 16 & 17: “ sigmatocoms ” for hexasters with S-shaped branch-rays, 
pp. 73 & 74, pi. xii, figg. 18 & 19; Schulze (56). 
The varieties and nomenclature of certain forms of monaxon siliceous 
spicules and of some hitherto considered as polyaxons: two fundamental 
subdivisions in the group of monaxons are distinguished; i, Pedinaxons, 
the axis of which lies in one plane ; u, Spir axons, the axis of which is 
a screw helix: the latter type may be further subdivided into a-spiraxons, 
