Species ofLw^axm from Yucatan. 227 



represent or describe our species, which differs in outward 

 form and appearance as well as in the details of its fibre and 

 its reticulation. The formula of Spongia fstularis, in the 

 twelfth edition of the ' Systema Naturae,' more properly applies 

 to one of the tubular Chalinas than to any of the Luffarida ; 

 and the observations of all the old writers on the subject 

 render it almost certain that they included both the tubular 

 Chalinas and tubular Luffarida under the specific name 

 u fistularis" the different examples of each then known being 

 taken to be varieties of the same species. 



In the sulcate sinuosities of the surface are many examples 

 of both siliceous-spiculed and calcareous-spiculed sponges of 

 humble and diminutive growth, also the stems or branches of 

 Tubuliporidge and the empty tube-cases of minute Serpulidae, 

 and many small patches of calcareous deposits ; and frequently 

 the dermal covering is seen to be sprinkled over with particles 

 of white sand and other debris, adhering firmly to it, or im- 

 bedded in the exposed fibrous network. 



Mr. Carter has kindly sent me a tracing of his " rough 

 sketch " of a specimen of the genus Luffaria from the East 

 Mediterranean, obtained fresh, and preserved in spirit, by 

 Admiral Spratt, who presented it to the British Museum 

 (No. 73. 4. 6. 9) ; to which Mr. Carter has obligingly added the 

 following remarks : — " It is tubular, about 6 inches long and 

 about | of an inch in diameter, also bears a somewhat smaller 

 specimen by its side. Thus the foregoing statement upon 

 Schmidt's authority, viz. that the ' family is proper to the 

 Tropical seas,' requires modification ; for it is also to be found 

 in the Mediterranean sea. Moreover from this fresh specimen 

 we learn that the aperture is circumscribed by a wide dupli- 

 cature of dermal sarcode, which in a ring-like form surrounds 

 the opening, and evidently performs the sphinctral diaphrag- 

 matic office common to vents generally." 



EXPLANATION OF PLATE VI. 



The figure is after an excellent photograph by Robinson and Thomp- 

 son, and gives the general character and appearance of the sponge faith- 

 fully ; but it is rather too broad in the lower half, and therefore does not 

 look quite so graceful as the specimen itself. 



