THE SESSILE BARNACLES. 285 



the infolded median parts of the parictes. These props also snp- 

 ])ort the low dome of the wall, Avliich without them would easily be 

 stove in by the impacts incident to its station on turtle shells. In 

 other embedded barnacles the base is smaller relative to the size of 

 the body-chamber. In some species the outer layer of the parietes 

 is permeated with minute pores, as in many other CoronuUnce. 



Only P. hexastjjlos is known from eastern American waters. The 

 other species described are: 



Platylepas decorata Darwin,^ Galapagos Islands, etc. 



Platyle/pas ophlophllui^ Lanchester,- Malay Peninsula, on the sea- 

 snake Enhydrls curtus, 



Platylepas krilgeri^ new name for Cryptolepas opIiiopMlus Kriiger.^ 

 Bangkok, Siam, on the sea-snake Distira; Gwadar, Belucliistan, on 

 the tail of IlydropMs. 



Though rather incompletely described, this species seems to be (]uite 

 distinct from P. ophiophUus Lanchester and P. decorata Darwin. 

 It certainly is not a Cryptolepas, 



PLATYLEPAS HEXASTYLOS (O. Fabricius). 



I'late G7, figs. 1-lc, 3. 



170S. Lcpas hexastylos O. Fabuicius, Skrivter af Naturlustorie-Selskabet, 

 VOL 4, Heft 2, p. 35, pL 10, figs. 1, 2. 



1524. Coromila biscxlobata De Blatnville, Dictionaire des Sciences Na- 

 turelk'S, voL 32, p. 379, pL 117, fig. 1 (republished in Manuel de Mala- 

 cologie, p. GOO, pi. 86, fig. 1). 



1525. Platylepas pulchra Gray, Annals of Philosophy, new ser., vol. 10, p. 

 105 (Corsica). 



1S25. " C. bisexloba Ranz," Gray (not of Ranzani), Annals of Philoso])h.v, 



new ser., vol. 10, p. 105. 

 . Coronula californicnsis Chenu, Illustrations Conchyliologlques, pi. 1, 



fig. 4 (sur les Cetac6s, Californie). 

 1854. Plafj/Jcpas bissexlobata Darwin, Monograph, p. 42S, pi. 17, figs. ^a-l(L 



(Mediterranean, on turtles; River Gambia and Honduras, on manatee; 



Moretou Bay, Australia, " apparently attached to the dug(jng of that 



coast "). 

 1S8L I'laiylcpas bissexlobata Blainville, P. Fischer, Bull. Soc. Zool. de 



France, vol. 9, p. 359 (New Caledonia, on Halieore dugony). 

 1903. Platylepas bissexlobata Blainville, Gkuvel, Nouv. Ann du Museum, 



ser. 4, vol. 5, p. 151, pi. 3, fig. 13 (Sicily; type of Coronula concentrica 



Valenciennes MS.). 

 1912. Platylepas bissexlobata (de Blainville) KriIger, Abhandl. K. Bayer. 



Akad. Wissensch., Suppl.-Bd. 2, 8 Abhandl., p. 13 (Timor Sea, on 



Chelmie ini hricata ) . 

 Type. — Probably lost; from the Mediterranean. 



1 1S54, Moiiosiapli, p. 429. 



2 Proc. Zool. Soc, London, 1902, pt. 2, p. .371 ; pi. 35, flgs. 5-56. 



^1012, Abhandlunjren der math.-phys. Klasse der K. Bayer, Akademio dor Wlsson- 

 Bchaftcn, Suppl.-Bd. 2, 8 Abhandl., p. 12, fit,^s. G-IO ; pi. ?,, figs. 7, 8. 



