!■ 



from Iceland ami Lahnnlor. Idl 



distinctive are tiie ovuid iivicuhiria and the absenee of the 

 snout-like sinus on the hnver margin of the aperture. But 

 the oval avicularia are conunonly present on the normal L. 

 trutpinosa, though, curiously cnougli, they have hitherto es- 

 caped observation, and are not figured or referred to by any 

 writer on tlie Polyzoa. They are, of course, frequently 

 wanting, as arc also the large pointed avicularia ; but in some 

 )art or other of the colony they may generally be detected, 

 [n some cases they are present in great numbers, two or three 

 on a cell, and are very irregularly placed. 1 have specimens, 

 probably from deep water, which ni some respects resemble 

 the Icelandic variety, in which there is an extraordinary deve- 

 lopment of them. As to the form of the mouth, it is very 

 variable in L. trispinosa. The spout-like projection is much 

 more markedly developed in some cases than in others ; at 

 times it is scarcely perceptible. Near the edge of the colony 

 cells may commonly be met with which bear the closest 

 resemblance to those of the arctic variety, especially in the 

 cliaractcr of the mouth, bein(j altogether destitute of the elevated 

 peristome. 



There is therefore no valid ground, in my judgment, for 

 erecting the present form into a species. It exhibits a very 

 slight divergence from the normal L. tri'sjmiosa, the absence 

 of the raised peristome marking, as stated above, an early 

 stage of growth in this species. The presence of the oval 

 avicularia is really one more proof of their identity. 



Smitt has given a good representation of the different states 

 which this species assumes, though he seems not te have 

 noticed the small avicularia. 



12. Lepralia tuhulosa^ Norman. (PI. XI. fig. 8.) 



Two or three specimens of this interesting species occur on 

 fragments of shell. In their perfect condition the cells are 

 armed with three or four spines. They are less thickly per- 

 forated than in the only British example which I have had 

 the opportunity of examining. On one of the specimens the 

 oooecia, which have not hitherto been described, are present ; 

 they are arcuate in form, shallow, depressed, and set very 

 far back behind the tubular neck of the cell. The surface is 

 smooth and silvery, with a few perforations. 



This remarkable species will stand as the type of a new 

 genus, for which I propose the name of Cylindro2)orella. 



[Shetland {Xorman) ; Wick [Pcach).'\ 



13. Lepralia hyalina, Linnajus. 

 On shells and on other Polyzoa, abundant. 



