FROM THE MERGUI ARCHIPELAGO. 



125 



gites, Smitt* and Manzoni, though in several points it differs 

 from the description and figure which these authors have given us. 

 The cells of the latter are more decidedly rectangular, and are 

 separated by conspicuous raised lines. The ocecium, though of 

 large size and rounded above, as in the present form, is of great 

 breadth and subtruncate in front (see Sinitt's figure 161) ; 

 whereas that of the Mergui variety narrows off towards the 

 oral extremity, which presents a rounded contour. There is 

 also a striking dissimilarity in the structure of the oral sinus, 

 which in the Mergui variety is small and slit-like, slightly en- 

 larged below, and occupies the centre of the lower margin, which 

 is perfectly straight. The same difference, however, and perhaps 

 in a more marked degree, is met with in the case of Sckizoporella 

 unicornis, and it cau hardly be taken in itself to indicate a 

 specific distinction. In the normal S. spongites the zoarium is 

 composed of several layers of cells placed one upon the other, 

 and in the upper stratum at least the zocecia are very irregularly 

 disposed ; they are turned in all directions, and without definite 

 plan. In the only specimen of the present form (a finely deve- 

 loped one) which I have examined, the zoarium consists of a 

 single layer of cells, and tbe latter are arranged with much regu- 

 larity in lines. These differences, however, may depend upon 

 age. The large scattered avicularia differ somewhat in shape in 

 the two forms, that of the Mergui variety being broadly spatulate. 



Family Selejtariid^:, Bush. 

 Cupularia, Lamouroux. 



Cupularia umbellata, Defrancef . (Smitt; Manzoni.) 



A considerable number of specimens occur in Dr. Anderson's 

 collection of a species of Cupularia, which I believe to be identi- 

 cal with the above. In its perfect condition the front of the cells is 

 covered with a semiopaque membranous investment, which carries 

 the orifice and opercular valve. In a specimen from which this 



* ' Floridan Bryozoa,' part ii. p. 42, pi. viii. figs. 161-163. Smitt identifies 

 his Floridan species with Eschara spongites of Pallas and Moll, but this identi- 

 fication must, I think, be accounted doubtful. Moll's figure seems to represent 

 a form of S. unicornis, Johnston, which is at once distinguishable from S. spon- 

 gites by the characters of the ooecium and the presence of the large spatulate 

 ayicularia. 



t This form clearly belongs to the Steganoporellidan series, and must be 

 transferred to it. 



