386 



G. K. VINE ON THE FAMILY DIASTOPOKID^. 



the Pea- Grit series (Mr. Longe's cabinet). One colony is five lines 

 by four ; and the ocecia are well developed, for there are no fewer 

 than from 25 to 27 swellings in various stages of development ; and 

 it is from this specimen that the drawings (Plate XIX.) are taken. 

 Measured across the cell- mouths, there are about six (or varying 

 from five to seven) cells to a line. Three ocecia occupy about the 

 same space. The earliest stages of colonial growth are disks with 

 free cells, flabelliform at later stages, ultimately presenting the 

 appearance of one continuous mass of immersed cells. On the 

 broken edge of a fragment of Mr. Walfords specimen I can count 

 from twenty to thirty layers, representing successive colonial 

 growths. 



It may be that some at least of the specimens of this type are the 

 Berenicea diluviana of authors, and the Biastopora verrucosa of 

 Milne-Edwards. Berenicea Archiaci, Haime, is closely related to 

 this species ; but the cells, and also the ocecia as figured by Haime*, 

 are not so characteristic of our own Oolitic series as D. ventricosa. 



3. Diastopora oolitica, mihi. Plate XIX. figs. 11-14. 



Zoarium circular or nearly so, completely adnate, and varying in 

 size from one to three lines in diameter either way. Zooecia short 

 and bulging near the distal, gradually contracting towards the 

 proximal end ; orifice variously shaped, the lower margin, in some 

 cases, slightly mucronate (?) ; primary cell excentric. Central 

 zocecia partially raised, becoming gradually depressed towards the 

 margin. Ocecia ? Tubes faintly punctured, and no " adventitious 

 tubules." 



Range from the Pea- Grit to the Great Oolite. 



Cabinets : (from several localities) my own ; Miss Gatty's, Xidling- 

 ton, Oxon ; Mr. Longe's, very rich, from Pea-Grit ; and also from 

 Mr. Walford's ; Museum of Practical Geology (several specimens on 

 shells). 



Hab. On stones and shells, forming small disk-like patches, more 

 frequently isolated than clustering. 



This delicate little species is the most abundant of the Oolitic 

 Diastopora. Prom its peculiar habit specimens are generally referred 

 by collectors to the B. obelia of JBusk ; and in my early identifica- 

 tions I was inclined to place it as a variety (var. oolitica) of that 

 species. After drawing and carefully working out the type I soon 

 found this to be impossible. The general habit is different ; the cells 

 are more closely packed, and their shapes are altogether different ; 

 and, above all, there is in none of the specimens I have examined 

 any indication of " adventitious tubules." Judging from Manzoni's 

 figure t, which he refers to Berenicea striata, J. Haime %, a doubt na- 

 turally suggested itself when correcting the proof of my first paper § 

 as to whether some specimens of this type may be referred to 

 Haime's species. There seems to be no identity either with that or 



* Bryozoa Jurassic Form. pi. ix. fig. 11. 

 + Fig. 79, Bryozoa of the Pliocene of Oastrocaro. 

 \ Reuss, Die Bryoz. des braunen Jura von Balin, &c. 

 § Quart. Journ. Geol. Soc. vol. xxxvi. p. 357, note. 



