|(V_> CEYLON PEARL OYSTER REPORT. 



In its intensely arenaceous habit and the consequent reduction of the proper skeleton, 

 this species resembles Esperella arenicola, RIDLEY and DENDY (1), and E. rm.s-.sv/, 

 DENDY (10), both from Bass Straits. It differs from the former, however, in the 

 absence of trichodragmata, and from the latter in the presence of sigmata. 



R.N. 293 ; 305 ; 334 ; 344 (Ceylon seas). 



Paresperella, n. gen. 



Encrusting or massive Esperellinte, with megascleres in the form of tylostyli or styli ; 

 with microscleres in the form of palmate anisochelse and serrated sigmata, to 

 which others (such as toxa) may be added. 



The existence of several esperelline species with serrated sigmata justifies the 

 erection of a new genus, of which the type will be CARTER'S Esperia serratohamata, 

 I am not aware that this very extraordinary form of spicule has hitherto been met 

 with in any other genus. 



There are probably at least three species of the genus Paresperella in the 

 neighbourhood of Ceylon, for in an indeterminable sponge encrusting a calcareous 

 nodule from " Deep water off Galle and onwards " I have found (as a foreign body) 

 a huge serrated sigma (Plate XL, fig. 3) like those of Paresperella serratohamata, but 

 far too large to be referred to that species. It measures 0'3936 millim. from bend to 

 bend and 0'0146 millim. thick in the middle of the shaft, while, according to 

 Mr. CARTER'S measurements, the corresponding spicule in P. serratohamata, though 

 large, measures only O'l millim. by 0'0052 millim. Curiously enough, P. serratohamata 

 was also first known from a single spicule. 



LINDGREN (86) has described, under the name Esperella macrosigma, a species of 

 Paresperella in which the serrated sigmata attain still more enormous dimensions, 

 measuring 0'48 millim. in length by 0'024 millim. in diameter. This species comes 

 from the straits of Korea, and it is quite likely that it occurs also in Ceylon waters 

 and may be represented by the single spicule above described. 



The genus is, of course, very closely related to Esperella, from which it has 

 evidently been derived. 



Paresperella serratohamata (CARTER) Plate XL, fig. 2. 



1880, Esperia serratohamata, CARTER (4). 



A minute specimen of this remarkable sponge occurs on a calcareous nodule in 

 association with Hymedesmia stelhvarians and Esperella parishii. The spiculation 

 agrees very well with Mr. CARTER'S description, but the apices of the tylostyles are 

 uniformly mucronate (Plate XL, fig. '2, a). This character is not mentioned in 

 Mr. CARTER'S description, and the figure which he gives of the tylostyle is on too 

 small a scale to afford satisfactory evidence. 



LAUBE (85) records this species from Vancouver, but I am doubtful, from the 



