298 Mr. T. Higgin on some Caribbean Sponges. 



into the usual cavities, which cavities communicate with each 

 other by means of the ordinary sphinctral openings in these 

 sarcodic expansions. The skeleton-spicules are of two forms, 

 namely a subcylindrical one, which is curved at the distance 

 of one third of its length, sometimes found pointed at the 

 long end so as to form a curved acuate, and a long fine straight 

 acuate spicule not only associated with this, but found also in 

 considerable numbers in the dermal sarcode. The subcylin- 

 drical spicule (fig. 12) measures 0*0068 inch in length by 

 •0003 at its thickest part ; and the long fine acuate (fig. 13) 

 is 0-01 inch long by 0*0002 inch in diameter. The flesh- 

 spicule is of one form only, viz. a minute birotulate, each 

 umbrella-like extremity of which is divided into twelve rays 

 or ribs connected with each other and with the shaft by the 

 usual falciform expansions (figs. 14 and 15), measuring 0*00053 

 inch in length, the diameter of the heads being 0*00016 inch 

 and the diameter of the shaft one tenth of that of the heads. 

 This minute flesh-spicule is liable to be passed over and its 

 beauty and form unobserved ; for the composition of the um- 

 brella-like head is not distinctly seen with a lower power than 

 a -i-th objective. Mr. Laurence Hardman of Rock Ferry, who 

 kindly undertook to verify the counting of the number of rays 

 or flukes, was fortunate enough to discover on the slide sub- 

 mitted to him a few rotulate extremities broken off from their 

 shafts and lying flat on the cover, the form of which was 

 beautifully seen under a -iVth. The finding of these heads in 

 this convenient position rendered the counting of the rays 

 easy, and enabled a correct drawing of an end view of one of 

 them to be made (fig. 15). 



Size. The specimens from the Spanish main are of the 

 massive and pyramidic form. In the latter the erect growth 

 is not more than 3 inches in height, with a base of from 2 to 

 3 inches in diameter ; while among the massive forms, which 

 cover pieces of coral, the largest specimen has a basal attach- 

 ment of 6 to 7 inches, and extends laterally in an irregular 

 lobe 5 to 6 inches. The branched form, known to us only by 

 the specimen in the possession of Dr. Allen of Jamaica, is 

 stated by him to extend to the distance of 2 feet from its root 

 or base, the diameter of the branches not exceeding 1 inch by 

 ^ to I inch. 



Log. Puerto Cabello, Caracas, and Bay of Kingston, 

 Jamaica. 



In the ' Argo ' collection there are some specimens of a 

 branched sponge from Nassau resembling the Jamaica exam- 

 ple in outward form, colour, skeleton, and structure, possessing 

 a skcleton-spicule of slender cylindrical form, but lacking 



