Mr. A. Hancock on new Species of Excavating Sponges. 241 



crowded that the usual dendritic character is scarcely discernible; 

 the terminal twigs are excessively short, and there are very few 

 spine-like processes; papillae few and large, measuring some- 

 times as much as -jV inch in diameter. Spicula pin-like, — inch 

 long, usually straight, occasionally a little bent, tapering gradu- 

 ally to the pointed extremity ; the head oval, mostly placed a 

 considerable way from the end, which is rounded ; frequently 

 the head is almost obsolete, sometimes entirely wanting; and 

 two heads are not by any means uncommon, one placed a little 

 below the other. 



A finely developed specimen of this species has penetrated the 

 shell of Spondylus gcederopus from the Mediterranean. It is 

 allied to C. celata, as is evinced by there being only one kind of 

 spiculum, and that pin-hke. The form of this organ, however, is 

 sufficiently characteristic ; but perhaps the colour of the sponge, 

 the delicacy of its texture, and the lobulated mode of its growth 

 are the best distinguishing features. 



Cliona Carpenteri. PI. VIII. fig. 4. 



Sponge, when dry, of a pale yellowish colour, formed of nu- 

 merous crowded angulated lobes scarcely -^^ inch wide, each 

 united to its neighbours by two or three short, much constricted, 

 cylindrical stems ; papillae about -n^V inch in diameter, not very 

 numerous, varying little in size, and scattered without apparent 

 order. Spicula of three kinds, — the first pin-like, -j-hr i»ch long, 

 straight, slender, rarely a little bent, with the head distinct, 

 perfectly globular, and exactly terminal : the second kind, which 

 is half tlie length of the first, is fusiform, unusually stout, with 

 occasionally an indistinct narrow nodule in the centre, where it 

 is suddenly bent ; the extremities are very sharply pointed : the 

 third form is very minute, being only tj-ttW ^^^ch long ; it is 

 usually straight, slightly fusiform, a little bent, and strongly 

 spined, with the extremities obtuse. 



Only one specimen of this species has been obtained ; it oc- 

 curs in the shell of a Serpula adhering to a Chama from Mazat- 

 lan, presented to the Newcastle Museum by Dr. P.P. Carpenter. 



EXPLANATION OF THE PLATES. 



Plate VII. 



Fig. 1. Spicula of Cliona Northumbrica : a, pin-like spicula; h, fusiform 



ditto; c, the minute or third form of ditto. 

 Fiff. 2. The minute or third form of spicula of C. vasiifica. 

 Fig. 3. Ditto of C. corallinoides. 

 Fig. 4. Ditto of C. gracilis. 

 Fig. 5. Ditto of C. Howsei. 

 Fig. 6. The minute or second form of spicula of C. lobata. 



