328 Rev, T. lliiicks's Contributions towards a 



minute particulars"^, but it differs essentially from .1/. Peachii, 

 var. octodentafa. From the latter it is distinguished by its 

 lageniform cells, the tall, neck-like, tubular peristome, which 

 is more than suberect, sometimes standing up almost at right 

 angles to the cell- wall, the rim bearing at the back and round 

 the sides about eight rather short spines set closely together, 

 the front margin carried up into a somewhat broad mucro, 

 often bi- or tridentate, and by its recumbent ooecium. It is 

 also furnished with an oral denticle, but it differs in form and 

 position from that of the variety octodentata. The cells of 

 M. spinosissima are very ventricose below, the surface is 

 smooth and shining, and a line of small circular pores runs 

 round the margin. I have no doubt of its distinctness from 

 the British form. 



In my " Report on the Polyzoa of the Queen Charlotte 

 Islands " I have described a supposed variety of the ])resent 

 species under the name AI. spinosissima, form major f. 

 Further consideration has convinced me that the supposed 

 variety is really a distinct species, with some marked charac- 

 teristics, of which the tubular structure in the cell-wall is 

 probably the most important. I propose to name it Mucro- 

 nella perforata. 



Miss Jelly also ranks Lepralia mnltispinata, Busk, as a 

 synonym of the variety octodentata J. Upon this I can only 

 remark that the general character and the details of structure 

 seem to me strikingly dissimilar in the two forms. This must 

 be apparent, 1 think, on a comparison of ^Ir. Busk's figure 

 with my own. I may direct attention sjiecially to the enlarged 

 figure of the orifice of L. imdfispinata §, which represents a 

 totally diflcrent structure from that which is characteristic ot" 

 J/, spinosissinui. 



In his 'Challenger' Report (part 1, p. 160) Busk has 

 described a variety of Mucronella ventricosa, which he lias 

 named muJtispinata and which he was inclined to think 

 might be identical with my il/. Peaclrii, var. octodentata. 

 His form, he contends, must be referred to M. ventricosa 

 rather than to M. Peachii , and judging from the detailed 

 account which he has given of it there can be little doubt 

 that he is right. On the other hand, some of the most 



* It is funiislied, like tlie fossil species, with tlie broad, flat, oral den- 

 ticle, dii'eot(Hl downwards and ovcrlianyiii>>- a large portion of tlie orilice, 

 lueiitioned by A\'aters. It may bo added that the njipor margin of the 

 primary orilice is distinctly crennlate. 



t " Report Pol. Q. C. l'." p. L>7 (sep.), pi. iii. fig. o. 



J 'Synonymic Catalogne,' p. 195. 



§ Quart. Journ. Micr. Sii., " /oopliytology," n. s. i. p. 7.'^, pi. xxxii. 

 fiff. 0. 



