Miscellaneous. 



159 



dredged oysters, which are frequently covered with Ascidise. The 

 locality whence my oysters were obtained is some twenty or thirty 

 miles from the Yorkshire coast, a little to the north of the river 

 Humber, and is known as the " Silver Pit." I annex a list of the 

 species hitherto detected in merely four gatherings, and this will 

 serve to show what may be expected when Ascidiae are examined 

 from other and ])ossibly more favourable localities. The letter A. 

 preceding the name denotes that the species occurs abundantly, F. 

 that it occurs occasionally (though less frequent than the first), and 

 R. that it occurs rarely — perhaps, for instance, one or two specimens 

 in a slide. 



List of Species. 



F. Eucampia zodiacus. 



F. Pinnularia distans. 



A. Pleurosigma lanceolatum, n. s. ; 

 resembling P. angulatum, but 

 has much coarser sti'iae, the 

 valve nearly straight, the cen- 

 tral line much curved, aud with 

 a faint depression running 

 across the centi-e of the valve. 

 The colour of the dry valve 

 is the same as in PI. transver- 

 sale. This form is constant, 

 and occurs in most gatherings 

 from deep water. 



F. Pleurosigma prolongatum. 



R. Pleurosigma, small form, with 

 ver)' acute extremities. 



R. PI. transversale. 



R. Pl.fasciola. 



A. Coscinodiscus concinnus, very 

 large. 



F. C. perforatus. 



A. C. excentricus, very fine. 



F. C. radiatits. 



A. Eupodiscus crassiis, fine. 



F. E. Ralfsii. 



R. E. sculptus. 



R. E. argus, in fragments. 



R. Eupodiscus, new species, with 

 cellular markings like a Cosci- 

 nodiscus, and a single process 

 near the margin. 



R. Amphiprora didymal 



R. Surirella fastuosa. 



F. Doryphora amphiceras. 



F. Doryphora, sp. ?, with parallel 

 moniliform stride. 



A. Actinocyclus undulatus, fine. 



R. ? Actinocyclus, sp. without rays. 



A. 

 F. 



Rhizoselenia sfyliformis, n. s. 



Rkizoselenia, small species, with 

 ends produced into a long, 

 slender, hau-hke filament. 



Rhizoselenia, a ciuious and 

 beautiful species, apparently 

 new, with feather- or scale-hke 

 markings. 



Siddulphia turgida, not entire. 



jB. Baillyii, fine. 



B. rhombus. 



B. aurita, in filaments. 



ChcEtoceras Wighamii. 



Chcefoceras, apparently two more 

 species. 



Nitzsckia Closteriiim ? 



N. lanceolatal 



Orthosira marina. 



? Orthosira, sp. 



? Asterionella, two species. 



Podosira maculata. 



? Melosira, sp. 



Stephanopyxis, sipecies; beautiful 

 form with cellular structure, 

 and furnished with clubbed or 

 forked horns at the ends of the 

 valves ; occm's in filaments of 

 four to five frustules. 



Stauroneis pulchella. 



Triceratium favus, fragments. 



T. striolatum. 



? Triceratium, curious form with 

 a star-like marking in the 

 centre of the valve. 



? Melosira, small form with lon- 

 gitudinal markings. 



Navicula Hennedyii. 



X. lyra. 



? Himantidium, sp. 



Hull, 27th July, 1857. 



