of the selenariadee, conescharellinid.e, etc. 403 



Appendages. 



The appendages of: the group have not received the attention they deserve, 

 and avicularia have frequently been in a wholesale way called vibracula as in 

 Conescharellina, which always has avicularia. The vibracula of Selenaria are 

 of a type quite different from anything known elsewhere, for they move in a 

 ring external to the vibracular chamber. 



In Lunulites there are various forms of appendages all of which have 

 been generally spoken of as vibracula, whereas vibracula only occur in a 

 limited number of forms in the family, such as Vibracella trapezoidea, Piss., 

 and Lunitiites mitra, Marsson (probably Vibracella). There are " ouycho- 

 cellaires" as figured by Beissel in L. Goldfussi* Hag., also they occur in 

 L. sella, Mars., and L. salebros, Mars., and probably in L. Beisseli, Mars., in 

 which there is an elongate chamber, usually broken down. L. cupulus, Busk 

 — L. gibbosa, Busk, also closely related to L. patelliformis, Maplestone (non 

 Marsson), has a long tapering seta divided at the end (PI. 30. fig. 16), which 

 is different from anything we are acquainted with, and probably must be 

 considered as avicularian. 



Lunulites of the radiata-type are the most common, and the avicularian 

 chamber has a projection on each side, but being rarely well preserved 

 they have consequently seldom been sufficiently figured. The name 

 Lunulites will probably ultimately be confined to this group, which will 

 iuclude such species as L. Hayenowi, Bosc (jion Beissel), L. transiens, 

 Gregory, &c. 



I f have on several occasions said that the real difference between avicu- 

 laria and vibracula consisted in the avicularia only having motion in one 

 direction, whereas vibracula have motion in all directions, and we must look 

 at the base of the appendages, or the chamber containing the muscles, &c, 

 to decide which of the two we are dealing with ; whereas the length of the 

 appendage has little classificatory value in the (Jheilostomata, for short, 

 round, or triangular avicularian mandibles may be replaced by whip-like 

 mandibles, as in Microporella coronata, &c. 



In Cupularia canariensis the central seta? are very short and small, though 

 quite mature, increasing in size to the periphery, where they are very long. 

 Correct appreciation of the differences between the two organs would have 

 led to their being more considered in classification in the present group, as 

 well as in other recent and fossil forms. Conescharellina has avicularia, 

 Cupularia and Selenaria have vibracula, Limulites, as it has been understood, 



* "Ueber die Dry. der Aacbner Kreidebildung," pi. 2. h'gs. 22, 24. Nat. Verb. Holland. 

 Maat. Wetenscbappen, vol. xxii., Haarlem 1865. 



t "Bryozoa," Kesultats du Voyage du S.i r . 'Belgica' in 1897-8-9, p. 27 (1904). 



