a S}/stem of the Calcarecrus Sponges. 179 



Genus 9. DuNSTEiiViLLlA, P>oweil)ank. 

 Gen. char. Skeleton of Sycarinm. Moutli-openin*:; with a 

 double peristomial crown (surrounded by a double circlet of 

 freely pi-ojecting spicules, an inner vertical and an outer hori- 

 zontal one). Five species. 



41. D. elexjans, Bb. Algoa Bay (Bb.). 



42. D. corcyrensis, O. S. Corfu (0. S.). 



43. *7). Schmidtii, II. Lagosta (O. S.). 



44. *D. Lanzerokr', 11. Lanzarote (M.-M.). 



45. '^B.furmosa, II. Barbadocs. 



Genus 10. Artynas, Gray. 



Gen. char. Skeleton as in Sycarmm. Mouth-opening 

 simple, without either proboscis or peristomial crown. Sto- 

 machal cavity chambered, traversed by irregular partitions." 

 Four species. 



46. A. compressuSj II. {Grantia coynpressa, J., var. b). 



Norway. 



47. A. ufricidu9j 11. [Ute utriculua^ O.S., var.). Green- 



land. 



48. * J . rhopalodes, 11. Norway. 



49. *u4. villosus, H. Antilles. 



Genus 11. Ute, 0. Schmidt {p.p.). 



Gen. char. Skeleton consisting of triradiate spicules in the 

 wall of the radial canals, of quadriradiate spicules, the fourth 

 ray of which projects freely into the stomachal cavity, in the 

 stomachal wall, and of simple linear spicules wliich lie parallel 

 to the longitudinal axis of the body and, being packed closely 

 together, fonn a firm external armour round the internal sys- 

 tem of radial canals. Mouth-opening simple, without either 

 proboscis or peristomial crown. Two species. 



50. U. glabra, O.S. Lagosta (0. S.). 



51. U. ensata, Gray {Grantia ensata, Bb.). Guernsey 



(Buckl.). 



Genus 12. *Cyathiscus, nov. gen. 



Gen. char. Skeleton consisting of triradiate spicules in the 

 radial partitions of the perigastric chambers, of quadriradiate 

 spicules, the fourth ray of which j)roject3 freely into the sto- 

 machal cavity, in the wall of the stomach, and of simple linear 

 spicules which run parallel to the longitudinal axis of the 

 body and, l»eing packed closely together, form a firm external 

 armour round the internal system of radial chambers. (The 



