CRATEROMORPHA PACHYACTINA. 75 



The specimen consists of a stalk and a large fragment of 

 the body projier. The former is about 100 mm. long and 18 mm. 

 by 26 mm. thick in the upper portion, but narrower below and 

 just above the swelling at the extreme base. In its general ap- 

 pearance, in the mode of transition into the body proper, in the 

 canal-system traversing the interior and in the ankylosis of 

 principal spicules in the lower portion, the stalk corresponds ex- 

 actly to that of C. meyerl. One thing which attracted my atten- 

 tion from the outset was the fact that on touching it with the 

 fingers it readily gave off' sharply pointed and disproportionately 

 strong-rayed spicules (hypodermnl pentactins), on which account 

 it was necessary to use extreme caution in handling it. 



The fragment left of the body-wall is in a mutilated condi- 

 tion but still s'lfiiciently w^ell preserved for determining the more 

 important features of the sponge. It is easy to conceive that 

 the specimen, when entire, had approximately the size and 

 general appearance of the two specimens of C. meijeri rugosa 

 figured in PI. V., figs. 14 and 1.3. Thé external surface is ex- 

 tremelv uneven on account of irregular elevations of varying 

 height. The wall is thick, measuring not less than 15 mm. in 

 thickness near its junction with the stalk. 



While the gastral surface is perforated with numerous large 

 apertures of excurrent canals and looks much like that of G. 

 nieyeri, the outer side of the wall presents a remarkably com- 

 pact and densely felted appearance, apparently due to an ex- 

 cessive development of the parenchymalia as well as to the fact 

 that the dermal layer is closely adherent to the parenchymal 

 mass. The subdermal space is scarcely perceptible, while incur- 

 rent apertures and canals, so far as can be recognized with the 

 naked e3^e, are narrow and widely separated from one another. 



