282 Mr. H. J. Carter on some West-Indian 



I can hardly doubt its existence generally under the same or 

 other representative forms. 



Order VI. HOLOEHAPHIDOTA. 



Family 1. Renierida. 



In the West-Indian collection, the Amorphina are repre- 

 sented by 'the ubiquitous Halichondria paniceaj Johnst. 

 (spicule, PI. XL fig. 8) ; the Isodictyosa by the British 

 species Isodictya simidans^ Bk. (spicule, PI. XL fig. 9) ; and 

 tlie Thalyosa by the West-Indian genus Thalysias, de F. et 

 M., in a repent form of the \\\\\ie 'A'^qqaq^ sidArkingularis. viz. 

 T. repenSj mihi, and the black one by T. carhoiiaria^ before 

 mentioned (spicules, PL XL figs. 10 and 11 respectively). 



Group 5. F I B u L 1 F E R A. 



Fihularia massa^ n. sp. 



Massive, solid, lobate, beautifully reticulate, lobes ending in 

 large vents respectively. Texture hard, but friable. Colour- 

 less when dry, Ppiidc or red when fresh. Surface even, regu- 

 larly reticulate, interrupted only by the openings of the vents. 

 Vents on the prominent parts large but not numerous. Internal 

 structure also ei^e^/y reticulate throughout, like the surface ; 

 traversed by the branches of the excretory canal-system ; fibre 

 composed of the skeletal spicules of the species. Spicules of 

 three kinds, viz. : — 1, skeletal, aeerate, smooth, cylindrical, 

 curved, round at the ends, about 80 by 4-6000ths inch in its 

 greatest dimensions (PI. XL fig. 13, «) ; 2, aeerate, smooth, 

 fusiform, nearly straight, in sheaf-like bundles when small, 

 becoming dispersed when large ; when hair-like in the form 

 of " trichites," in bundles about 20-6000ths inch long, and 

 when large and dispersed about 3o by 1-GOOOth inch in its 

 greatest dimensions (figs. 13, /), c) ; 3, flesh-spieule, bihamate, 

 smooth, simple, C-shaped, siguioid, about 4-GOOOths inch long 

 (fig. 13, d). No. 1 is chierty confined to the skeletal fibre; 

 nos. 2 and 3 are abundantly dispersed throughout the sarcode. 

 Size of specimen, which is only a fragment, about 4^ inches 

 long, 2 broad, 2 high. 



Hub. Marine. 



Loc. Long Key Island, Nassau. 



Ohs. This in structure is a very beautiful species, on account 

 of the uninterrupted regularity of its reticulation throughout, 

 which literally is " isuJietyal." Tlie larger acerates are no 

 doubt derived from the hair-like small ones, which, coming 



