476 Miscellaneous. 



by the discoverer to his friend ^Ir. John A. liyder, in acknow- 

 ledgment of much excellent advice, assistance, and encouragement. 



Tubella pcnnsi/lvan ica . 



The genus TahcUa, as established by Mr. H. J. Charter, February 

 1881, was represented by four species, three originally described by 

 Dr. Bowerbank (as Spongillas), and one by Mr. Carter, all collected 

 in the Amazon river, South America. It does not appear that any 

 have been described from other localities. It was therefore with much 

 pleasure and some surprise that, while examining material collected 

 at Leheigh Gap, Pa., in November last, Mr. Potts came upon un- 

 doubted specimens of the same genus. It differs from Mei/enia in 

 the fact that the rotulse of the spicules surrounding the statospheres 

 are of unequal diameters, the larger one being placed next the 

 chitinous coat. This species, whose peculiarities do not tally with 

 those of any of the four above mehtioned, maj' be thus de- 

 scribed : — 



Sponge minute, incrusting, thin; the skeleton -spicules arranged 

 in a simple series of single non -fasciculated spicules, in the inter- 

 spaces of which the statospheres are abundant. 



Skeleton-spicules very variable in si/e and in shape, but all 

 entirely and coarsely spined ; rounded or abruptly pointed at the 

 extremities. 



Dermal spicules absent or undetermined. 



Statospheres numerous, small ; granular coating thin, but ex- 

 tending to or somewhat beyond the outer ends of the birotulates. 

 Length of the inequibirotulates about equal to the diameter of the 

 larger disk, which is placed against the chitinous coat. Margin of 

 larger disk generally entire, subcircular ; outer surface Hat, table- 

 like, the margin sometimes slightly incurved. This surface is not 

 unfrequently warped or twisted into an irregular outline. The outer 

 disk, in the great majority of cases, is about one fifth of the diameter 

 of the inner, but varies from, say, one sixth to equality, which is, 

 however, rarely observed. Its margin also appears to be generally 

 entire, but it is undoubtedly sometimes divided into six or eight 

 rays. The inner surface of the larger disk is also occasionally 

 marked with rib-like rays ; and still more rarely the margin between 

 the rays is wanting. 



These, as before stated, are all the species whose novelty has been 

 definitely determined ; but amongst the large amount of material 

 collected are doubtless others, belonging to the genera Spongilla and 

 Mei/enia, whose distinguishing peculiarities are less obvious, and 

 where close study will be needed to define them. — Proc. Acad. Nat. 

 ScL Philad., Jan. 10, 1882, p. 12. 



Bestoration of the DisJc in Opliinram. By A. E. Verkill. 



That Ophiurans restore their rays with remarkable facility when 

 broken, or entirely lost, is well known. In examining a large 

 series of Amphinra abdita, Y., collected in the harbour at IVoank, 



