194 Dr. J. W. Gregory — A Revision 



Fig. 3. Scorpio fulvipes, nat. size. 



Fig. 4. Opisthophthalmus capensis, X f . l.n., longitudinal nerve. 



Fig. 5. Uroplectes triangidifer , X -f. 



Fig. 6. Portion of ovary of Scorpio fulvipes. 



Fig. 7. Portion of ovary of Fuscorpius italicus, with unfertilized eggs. 



Fig. 8. Portion of the same, with embryos in the ovarian tube. 



Fig. 9. Portion of edge of lung-book lamella of Vejovis, sp. (spinous 



type). 

 Fig. 10. The same of Euscorjrius italicus (arcade type). 

 Fig. 11. The same of Buthus nigrolineatus (reticulate type). 



XXVII. — A Revision of the British Jurassic Bryozoa. — 

 Part V. The Families Idmoniida} and Entalophoridte. 

 By J. W. Gregory, D.Sc, F.G.S. 



[Continued from p. 155.] 



Family Idmoniidae. 



Diagnosis. — Cyclostomata Tubalata in which the zooeeia 

 are simple open tubes and grow into adnate or erect branching 

 zoaria. The zoarium is branched and the zocecia open only 

 on one side of it. The apertures are arranged in regular 

 transverse series, usually alternately arranged. 



Genus Idmonea, Lamouroux, 1821. 



Diagnosis. — Zoarium adnate or erect. Branches ridged or 

 triangular in section. Zocecia in regular, transverse, and 

 usually alternate series. The zoarium is branched and the 

 branches usually radiate from a centre. The branches some- 

 times anastomose. 



Type species: Idmonea triquetra, Lamx. 1821. 



1. Idmonea triquetra, Lamouroux, 1821. 



Idmonea triquetra, Lamouroux, 1821, Expos. m6th. p. 80, pi. lxxix. 



figs. 13-15. 

 Non Idmonea triquetra, Walford, 1889, Bry. Shipton, Tart I., Quart. 



Journ. Geol. Soc. vol. xlv. pp. 568, 509, pi. xviii. fig. 13, pi. xix. 



figs. 3, 4. 

 Reptotubigera triquetra, d'Orbigny, 1852, Pal. franc., Terr. criSt. t. v. 



p. 751. 

 Idmonea gracilis, d'Orbigny, 1849, Prod. Pal. t. l. p. 317. 



Diagnosis. — Zoarium composed of triangular branches, 

 beside' each of which is a thin flat selvage. The branches 

 dichotomize repeatedly. 





