BRYOZOA 4 i 



Cribrilinidse 



I cannot at ail follow Jullien when he replaces the family Cribrilinidœ by the Costulidœ, 

 and think, that instead of considering the ribbed structure of the front as of chief importance 

 we may hâve to break up the Cribrilinidœ, by placing various species elsewhere, and only 

 considering the ribbed structure of generic value, or in some cases of perhaps spécifie value, 

 as already hinted at by Harmer. 



A radiate structure of the pores is found in a great number of gênera, then between 

 the pores we may get tubercles, formed as in various species of Lepralia, when a young growing 

 zoœcium shows many of the characters of Cribrilina, the surface in the growing edges is first 

 formed by a smooth calcareous growth, and any ridges or knobs are subséquent ; thèse cannot 

 however be compared with spines. A better knowledge of the growing stages is much required. 

 In such species as Pseudqflustra palmata Sars, Cyclicopora polaris sp. nov. and a large number 

 with a row of pores round the border, the pores are first formed, and then a ridge grows 

 between each pore. 



The ribbed structure seems to be foreshadowed in many cases, and we find the cribrilline 

 form with Microporellidan structure ; with Gemellipora aperture, as in C. clithridiata Waters ; 

 and as mentioned by Harmer also in Catenicella. 



The choice of the fossil Esharella Arge d'Orb. to be the type, and the only représentative 

 of the genus Costula, from which the family name is taken, is peculiarly unfortunate, as 

 according to Canu the fossil is lost, and there is every probability, that the figure and description 

 given by d'Orbigny were from a worn spécimen. Hincks discusses the Costulidœ in & Critical 

 Notes on the Polyzoa » (Ann. Mag. Nat. Hist., ser. 6, vol. V, p. 8g, &c). 



Cribrilina projecta sp. nov. 



(PI. II, figs. I 4 <l-rf) 



Zoœcia broadly oval, with about 11-14 rows of pores on each side, at the junction of 

 two or three zoœcia there is a small raised triangular avicularium, which has the appearance 

 of being at the proximal end of the zoœcium, whereas it is in interzoœcial spaces. The 

 mandible (fig. a) is narrow and long. The peristome, raised on the distal edge, divides into 

 prominent processes, and the proximal edge is also sometimes raised. Whether one or two 

 pores, immediately below the peristome, belong to the surface perforations or are suboral 

 pores is uncertain, and the ovicells are unknown. There are pore chambers, and the primary 

 zoœcium has 12 spines. 



There are no complète polypides, histolysis having commenced, but sections show brown 

 bodies and groups of cells that had not lost their vitality, also the avicularian muscles, but 

 not the gênerai muscular system, while sections eut longitudinally show in the outer membrane, 

 between the pores, cavities containing granular bodies (figs. 14c, d). The front membrane 

 ofthe zoœcial chamber, or perhaps we should say the base of the compensation sac, is much 

 thicker than the other membranes, apparently being somewhat chitinous. This differs from 

 C. setirostris MacG. in having so many more pores, and in the smaller avicularia not having a 



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