13 



concludes righth' therefore in saying that the calcification, which appears within 

 the marginal spines in the primary zooecium of Schizoporella vulgaris, is a Cryp- 

 tocyst, and such is found at the same place in many malacostegous Cheilostomata. 

 A Cryptocyst of this sort is not only very plainly hollow or depressed, which is 

 in contrast to the arched Gjnnnocyst, but also varies as a rule from the latter by 

 having a more or less grained or rugged surface. 



We can find all sorts of transitions between a completely membranous and 

 completely calcified frontal wall among the forms without a compensation sac, 

 and for which we have suggested the name: Anasca. The whole calcified part 

 is sometimes a Gymnocyst, sometimes a Cryptocyst and sometimes, both kinds 

 of calcification may appear at the same time, the Cryptocyst springing from the 

 Gymnocyst where the latter passes over into the membranous area. We can dis- 

 tinguish between a distal part, a proximal part and two lateral parts for the 

 Gymnocyst as well as for the Cryptocyst. The distal part is in most cases the 

 least developed because of the position of the aperture in the distal part of the 

 zocccium, and may in the Cryptocyst not seldom be quite missing, while the 

 proximal part as a rule has the largest extension. A peculiar exception is found 

 in the form which Busk describes as Diachoris magellanica, v. distans^, but which 

 must undoubtedly be regarded as an independent species. The proximal part is 

 here very feebly developed, whilst the two lateral regions are very broad and 

 only separated by a split in the middle line of the zooecium. hi very few cases, as in 

 Metnbranipora delicatula, the proximal part may grow out as a free lamina which 

 is not connected with the lateral regions, and when such a lamina again meets 

 these distally we have the peculiar condition known in Caleschara denticnlata, in 

 which the frontal wall is furnished with two long and narrow fissures. The distal 

 part may in some avicularia, for instance in the lyre-shaped forms, exceed in 

 extent the proximal (PI. VI a, fig. la, 2 a, 3 a). While a Gymnocyst in the Flus- 

 tridae is either quite lacking or only represented by a faint marginal part, 

 there can in a number of species, as e. g. Fl. denticalata, Fl. carbacea, Fl. serru- 

 lata, Fl. biseriata, Fl. cvibriformis and Fl. Sch0nam, n. sp., appear a feeble, more 

 or less knotted Crj'ptocyst, the proximal part of which is most developed. While 

 the Cryptocyst appears very late in Fl. denticulata and therefore can only be 

 found in older parts of the colony, we find it very early developed in Fl. serru- 

 lata and Fl. carbasea, in which species it is only lacking in the very youngest 

 zocecia. Longitudinal and transverse sections through such a colony (PI. XXI, 

 fig. 10 a — 12 a) show that this Cryptocyst, which Waters^ calls the chitino- 



' 8, p. 59; '' 109, p. 280. 



