306 REPORT— 1873. 



But, notwithstanding my profound respect and appreciation of Professor 

 Owen's comparative anatomical studies and his conclusions thereon, I find 

 great difficulty in adopting this view, because it does not accord ivith those 

 generally entertained regarding similar structures in other orders of Crus- 

 tacea ; neither will it harmonize with the earliest known forms of the Xi- 

 PHosuRA, nor with the larval development of recent Limulus as made known 

 by the researches of Packard* and Dohrnf. 



Prof. Owen names the small modified bifid median appendage behind the 

 mouth o{ Limulus the "chilaria"J; this is doubtless the homologue of the 

 great metastomial plate of Ptenjgotus^. 



Dr. Packard, when contrasting (in his work on Larval Limulus, oj). cit.) the 

 Mekostomata with the Trilobita, inadvertently calls the " Metastome " the 

 " Hypostome," and contrasts it with the Hyjpostome in Trilobites, in which no 

 lower lip exists. 



Referring to the habits of the Pterygoti, Prof. Owen considers they were 

 those of burrowers like the Limuli ; but their bodies and broad swimming- 

 feet seem preeminently fitted for natation. 



On the other hand, he thinks IJmulus could not walk well, but only crawl 

 and burrow. I have frequently seen them alive in the Aquaria at the 

 Zoological Gardens ; and they walked with considerable ease and activity on 

 the tips of their toes. They are, however, true burrowers by habit. 



Prof. Owen is willing to accept the theorj' of development of the Mero- 

 STOMATA from a typical and common life-form, but by " Secondary causes or 

 laws," 110^ by Natui'al selection (p. 501 op. cit.). 



Several additions have been made to the Carboniferous Phyllopods, the 

 species of which I have described in conjunction with my friend Mr. Eobert 

 Etheridge, jun. (of the Geological Survey of Scotland) ; some notice of these 

 wiU be found in the Transactions of the Sections (C), in a separate paper. 



Of Cretaceous forms I have examined several new species, among which 

 are three examples of the carapace of a small Gault Crustacean from Polkestonc 

 (near to Diaulax Carteri, from the Cambridge Greensand), which I have 

 named Z>. feliceps, two small forms of Scyllariclia, the genus hitherto only 

 known in the Eocene Tertiary : — 



Scyllaridia Gardner!, sp. nov. 

 pwictata, sp. nov. 



A small Crangon? of doubtful determination, with two delicately serrated 

 lines on the anterior half of the carapace in front of the nuchal furrow, and 

 the hinder part armed with very minute spines, the surface of the carapace 

 being ornamented with very minute and scattered serrations ; the carapace, 

 hands, and detached body-segments of which are aU of a glistening black 

 enamel. I have named this Mesocrangon atra ||. 



Fifteen years ago Mr. Charles Gould, F.G.S., described^ a very imperfectly 



* " The Development of Limulus jpolyphemus" by A. S. Packard, Jun., M.D., Mem. 

 Boston Soc. Nat. Hist., 1872, vol. xi. pp. 155-202, pis. iii.-v. 



t " Zur Embryologie iind Morphologie des Limulus 'polypi leinus,^' von Dr. Anton Dohrn, 

 Jenaische Zeitschrift, Band vi. Heft iv. p. 580, Taf. 14 und 15' (1871). 



\ From -/(eCkapiov, a small lip (Owen, op. cit. p. 464). 



§ As pointed out by me : see Brit. Associatiou Keports, Edinburgh, August 1871, Fifth 

 Eeport on Fossil Crustacea, p. 53. 



II These specimens are from the collection of J. Starkie Gardner, Esq., F.G.S., who has 

 kindly placed them at my disposal for examination with others. 



^ Quart. Journ. G-eol. Soc. 1859, vol. xv. p. 237. See also Bell's Mon. Pal. Soc. Crus- 

 tacea of the Gault and Greensand, 1862, p. 1, pi. i. figs. 2 and .3. 



