132 



cellaria scahrd) it seems natural to suppose that these hefeiozoa^cia in this family 

 always have an inner wall of their own. In Caherea and CaberielUt I have found 

 a septum dividing the vibracular chamber into two, of which only the distal 

 may contain the muscles. While the od'cia in the majority of this family are 

 hyperstomial, they are endozooecial and more or less deeply immersed in Biujii- 

 lopsis Peachi, Ihigulopsis cuspidala, Menipea criistdllina, M. cernicornis, M. Biiski. 

 M. triseriata and M. spicata. In M. crystallina they are enclosed in kenozoa'cia 

 with a large membranous frontal area, while in the others they are immersed 

 in ordinary zoa'cia, in such a way, however, as to appear more or les promi- 

 nent on the zooecial surface. In M. Hiiski and M. cervicornis the distal part of 

 the ocHcium is covered by a granular cryptocyst. In a smaller number of species 

 the ectood'cium is wholly calcified, e. g. in Scriipocellaria levnatu^, Scrupocellaria 

 reptans and Scnip. scruposa, but in most cases a larger or smaller [iroximal part 

 is membranous and accordingly appears as a rounded or triangular area, clearly 

 distinguishable from the calcified distal part. This is seen e. g. in Caheriella 

 benemiinita (PI. XXII, fig. 8 a), Menipea roboratu (PI. II, fig. 7 a) and M. ligulata 

 (Pi. II, fig. 8 a). 



This famih' is one of the most natural and most sharplj' delimited, and the 

 differences shown by the zooecia in respect to the armature of spines, develoj)- 

 ment of gymnocyst and cryptocj'st etc., are all subject to such great variation 

 from species to species that no generic importance ought to be attached to them. 

 The division of the genus has therefore hitherto been based chietlj' on the struc- 

 ture and appearance of the heterozooecia, and for the present I am unable to 

 delimit them in a more natural way. In earlier as well as in more recent times 

 attempts have been made to divide the large genus Menipea, e. g. by Gray, Mc 

 Gillivray and Waters. But as I consider it superfluous to enter into a critical 

 examination of the genera Emma' and Craspedozoum^, proposed by the two 

 former authors, I shall limit myself to a closer examination of the divisions made 

 bj' Waters^. This author discusses the subject as follows: »In the descri[)tion of 

 the species, it is now shown that in the Celhilariidae there are two distinct kinds 

 of articulation. In the larger number the new branch is given olf from a small 

 chamber formed for the purpose. As the type of this section Menipea Baski is 

 figured (PI. I, fig. 10); aiul I propose to restrict Menipea to those forms having 

 this kind of articulation; and it will then include ^1/. Buski, Mac (1., ^1/. crystal- 

 lina. Gray, M. njatluis, Thompson, M. ceri>icornis, Mac. G., M. conipacta, Mac. G. — 



' In tilis species which has hitherto Ijccmi referred to the genus Meiiijwa, I liave found a viliia- 

 cuhiiii, but without nagcllum. - 2, p. 27. " G9, p. 131. ' 111, p. 2. 



