Description of Ommatocarcinus corioensis. 359 



Omniatocarciuus corioensis is very closely related to 0. 

 mac2;illivrayi, White,! occurring in Queensland and New 

 Zealand. There are, however, differences in the form of the 

 carapace. The antero-lateral spine is directed slightly back- 

 wards in the recent species, and runs out straight in the fossil. 

 The carapace again in the fossil species is squarer and less 

 attenuated behind than in 0. macgillivrayi. The transverse 

 ridge is further back in 0. corioensis, and cuts the lateral 

 margin at a point distant from the base of the spine by the 

 length of the spine itself, while White's figure shows it running 

 nearly to the base of the spine. The cardiac area in the fossil 

 is much more tumid and strongly marked than is shown in 

 W^hite's figure. 



There is again a striking difference in the length of the 

 chelipeds in the fossil and the Queensland forms, but the New 

 Zealand specimens, according to Miers,^ have theirs much 

 shorter than the Queensland examples, wliich are still available 

 for comparison in the British Museum. White savs that in the 

 latter the chelipeds are two and a half times as long as the 

 carapace, measuring it from spine to spine ; these are adult 

 males ; while Miers gives the measurements as about equal for 

 the New Zealand ones. In this respect the fossil is intermediate, 

 the measurements being about as 5 is to 4. There is no 

 spinule in the middle of the upper margin of the merus of the 

 cheliped in the fossil, while it is present in the recent species ; 

 otherwise the distribution of granulations and small spines 

 seems the same. 



The specimens that I gathered were found in the cliff sections, 

 extending for some miles on both sides of Port Campbell, which 

 is about ten miles north-west of the well-known "' Gellibrand '' 

 section. The beds are nearly horizontal, and can be traced for 

 many miles along the coast, though in many places they are 

 inaccessible owing to the precipitous nature of the cliffs. The 

 sandy clays containing the crabs overlie the blue clays of the 

 '' Gellibrand " section which, near the Glenample homestead, 

 plunge rather abruptly beneath them. 



1 White in Macgillivray, " Narrative of the Voyage of the Rattlesnake," 1852 

 Appendix, p. 393, pi. 5, fiff. 1, la. 



2 Hep. "Challenger," Zoology, vol. 17, p. 248, 



2a 



